Present Perfect vs Past Simple

(I have finished  vs  I  finished)

PRESENT PERFECT 

The present perfect tense is used :

• To talk about an action which started in the past and continues
       today :
  
       For and since are used to express duration. 
  • I have lived here for 10 years.  I have lived here since 2005.
        (I arrived 10 years ago and I am still here.)

• To refer to past events in an unfinished period of time.
  • I have written two letters today.
        (Two letters are written but today is not finished.)

• To refer to past events that have just happened or been announced :
  • There has been a plane crash near the coast.
        (We know the event took place but we don't know when.)

• To talk about a past action with a result in the present.  :
  • I've broken my arm.  I can't drive (= because my arm is broken now.)

• To talk and ask about experiences or accomplishments up to the time
      of speaking :
  • "I'm a writer. I've written 9 books."
  • "Have you ever written a biography?" "No, never."

PAST SIMPLE

The Past Simple is used:

• When the period of time is finished.
  • I wrote two letters yesterday. (Yesterday is finished).

Present Perfect Tense

Present Perfect Simple
Affirmative	Negative		Interrogative
	Long Form	Contracted Form
I have done	I have not done	I haven't done	Have I done?
You have done	You have not done	You haven't done	Have you done?
He/she/it has done	He/she/it has not done	He/she/it hasn't done	Has he/she/it done?
We have done	We have not done	We haven't done	Have we done?
You have done	You have not done	You haven't done	Have you done?
They have done	They have not done	They haven't done	Have they done?
Present Perfect Continuous
Affirmative	Negative		Interrogative
	Long Form	Contracted Form
I have been doing	I have not been doing	I haven't been doing	Have I been doing?
You have been doing	You have not been doing	You haven't been doing	Have you been doing?
He/she/has been doing	He/she/it has not  been doing	He/she/it hasn't been doing.	Has he/she/it been doing?
We have been doing	We have not been doing	We haven't been doing	Have we been doing?
You have been doing	You have not been doing	You haven't been doing	Have you been doing?
They have been doing	They have not been doing	They haven't been doing	Have they been doing?

The present perfect is used to refer to actions which take place in an
unfinished time period up to the time of speaking.

• The present perfect continuous tense is used to refer to an action
      which started in the past and continues today.

Past Continuous Tense

Affirmative	Negative		Interrogative
	Long Form	Contracted Form
I was playing	I was not playing	I wasn't playing	Was I playing?
You were playing	You were not playing	You weren't playing	Were you playing?
He/she/was playing	He/she/it was not playing	He/she/it wasn't playing	Was he/she/it playing?
We were playing	We were not playing	We weren't playing	Were we playiing?
You were playing	You were not playing	You weren't playing	Were you playing?
They were playing	They were not playing	They weren't playing	Were they playing?

The past continuous tense is used :

• To talk about a continuous action which took place at a specific time in the
   past :
  • Yesterday evening, at 9 o'clock, I was watching television.
  • What was I doing at 11 o'clock this morning? I was gardening.
• It is also used in sentences with when or while, to refer to an action which
   was taking place when a shorter, brief event occurred.
  • Yesterday, while I was watching television, the phone rang.
  • When my husband arrived home yesterday, I was cooking dinner.

Past Simple Tense

(example : to play)

• The past simple tense of regular verbs is formed by adding - ed to the infinitive
  (for example: -  Infinitive : to play   Past Simple : I played)


• The auxiliary did is used to form the negative and interrogative forms

Affirmative	Negative		Interrogative
	Long Form	Contracted Form
I played	I did not play	I didn't play	Did I play?
You played	You did not play	You didn't play	Did you play?
He/she/it played	He/she/it did not play	He/she/it didn't play	Did he/she/it play?
We played	We did not play	We didn't play	Did we play?
You played	You did not play	You didn't play	Did you play?
They played	They did not play	They didn't play	Did they play?

The past simple tense is used to talk about finished actions in a finished period of time,
for example :

• Yesterday evening I played tennis with a friend.
• Last year I started taking tennis lessons.
• When I was at school I hated history.
• Five minutes ago I finished the report for my boss.
• Last week I attended a meeting in Tokyo.

Present Continuous Tense

Affirmative	Negative		Interrogative
	Long Form	Contracted Form
I am playing	I am not playing	I'm not playing	Am I playing?
You are playing	You are not playing	You're not playing	Are you playing?
He/she/it is playing	He/she/it is not playing	He/she/it's not playing	Is he/she/it playing?
We are playing	We are not playing	We're not playing	Are we playing?
You are playing	You are not playing	You're not playing	Are you playing?
They are playing	They are not playing	They're not playing	Are they playing?

The present continuous tense is used:

To talk about continuous activities :

• At the time of speaking :
  • I am reading this page now.
• Around now, in a more general sense :
  • I am learning English this year.

To talk about planned future activities or intentions :

• Tom and Mary are coming to dinner tomorrow. They called to confirm.

• I am spending my holidays in Australia. I have already booked my flight.

Present Simple Tense

Affirmative	Negative		Interrogative
	Long Form	Contracted Form
I play	I do not play	I don't play	Do I play?
You play	You do not play	You don't play	Do you play?
He/she/it plays	He/she/it does not play	He/she/it doesn't play	Does he/she/it play?
We play	We do not play	We don't play	Do we play?
You play	You do not play	You don't play	Do you play?
They play	They do not play	They don't play	Do they play

The present simple tense is used :

• To talk about regular activities :
  • John plays tennis once a week.
  • We start work at 9 a.m. every morning.
  • Mary goes to visit her parents on Sundays.

• To talk about tastes :
  • Peter likes Chinese food.
  • Julie doesn't like classical music.
  • Most children love chocolate.

• To talk about facts :
  • The sun rises in the east.
  • In Europe, the weather is cold in winter.
  • Authors write books.

Shall and Will

What is the difference between shall and will?

Shall is not used often in modern English especially in American English. In fact, shall and will have the same meaning and are used to refer to the simple future. They are use as follows:

• will is used with all persons
  

  I, you, he, she, it, we, they	will	go there

• shall is used with the first person singular and plural
  

  I, we	shall	go

• The short form of will and shall is 'll

  I, you, he, she, it, we, they	will or 'll	call you

  
  

  I, we	shall or 'll	call you

• In the negative, the short forms of will not and shall not are won't and shan't respectively
  

  I, you, he, she, it, we, they	won't	give up

  
  

  I, we	shan't	give up

Uses of shall

It should be noted that shall is often used to make suggestions, offers or ask for advice. It is used in questions as follows:

• Shall we stay or go out?
• Shall we dance?
• Shall I get his phone number if I meet him?
• What shall I do to get rid of my acne?

Shall and Will

What is the difference between shall and will?

Shall is not used often in modern English especially in American English. In fact, shall and will have the same meaning and are used to refer to the simple future. They are use as follows:

• will is used with all persons
  

  I, you, he, she, it, we, they	will	go there

• shall is used with the first person singular and plural
  

  I, we	shall	go

• The short form of will and shall is 'll

  I, you, he, she, it, we, they	will or 'll	call you

  
  

  I, we	shall or 'll	call you

• In the negative, the short forms of will not and shall not are won't and shan't respectively
  

  I, you, he, she, it, we, they	won't	give up

  
  

  I, we	shan't	give up

Uses of shall

It should be noted that shall is often used to make suggestions, offers or ask for advice. It is used in questions as follows:

• Shall we stay or go out?
• Shall we dance?
• Shall I get his phone number if I meet him?
• What shall I do to get rid of my acne?

Must and Have to

What's the difference between must and have to?

Must and have to are modal verbs in English. This page will guide you to the proper use of these modals.

Must

1. We use must to make a logical deduction based on evidence. It indicates that the speaker is certain about something:
Examples:

• It has rained all day, it must be very wet outside.
• The weather is fantastic in California. It must a lot fun to live there.

2. Must is also used to express a strong obligation.
Examples:

• Students must arrive in class on time.
• You must stop when the traffic lights are red.
• I must go to bed.

Modals in the Present and Past

Modals in the present and past

Generally speaking modals in the past have the following form:

• modal + have + past participle

Example:

• Present:
  You should see a doctor.
• Past:
  You should have seen a doctor

Except for modals that express obligation,ability and lack of necessity:

• Obligation:
  Present = I must / have to work hard. -- Past = I had to work hard.
• Ability:
  Present = I can run fast. -- Past = I could run fast when I was young.
• Lack of necessity:
  Present = You don't have to / needn't take your umbrella. -- Past = You didn't have to / didn't need to take your umbrella.

Modal verbs and their meaning

What are modal verbs?

Modals (also called modal verbs, modal auxiliary verbs, modal auxiliaries) are special verbs which behave irregularly in English. They are different from normal verbs like "work, play, visit..." They give additional information about the function of the main verb that follows it. They have a great variety of communicative functions.
Here are some characteristics of modal verbs:

• They never change their form. You can't add "s", "ed", "ing"...
• They are always followed by an infinitive without "to" (e.i. the bare infinitive.)
• They are used to indicate modality allow speakers to express certainty, possibility, willingness, obligation, necessity, ability

List of modal verbs

Here is a list of modal verbs:

can, could, may, might, will, would, shall, should, must

The verbs or expressions dare, ought to, had better, and need not behave like modal auxiliaries to a large extent and my be added to the above list

Use of modal verbs:

Modal verbs are used to express functions such as:

1. Permission
2. Ability
3. Obligation
4. Prohibition
5. Lack of necessity
6. Advice
7. possibility
8. probability

Interjections

What are interjections?

In grammar, an interjection is a part of speech or (a lexical category) which is used to show a short sudden expression of emotion. Examples of common interjections in English are hi and hey.

Using interjections

Interjections are rarely used in academic or formal writing. They are, however, common in fiction or artistic writing.
Interjections are often used with exclamation mark.

Examples of interjections

This is a list of some English interjections:

• Ah - Ah, what a delicious meal!
• Aha - Aha, now I see what you mean!
• Alas - I love football but, alas, I have no talent as a player.
• Eh - Eh? Say it again - I wasn't listening.
• Er - "Is he handsome?" " Er, well - he's got a nice friendly sort of face though he's not exactly handsome."
• Hello - Hello, Paul. I haven't seen you for ages.
• Hey - Hey! What are you doing with my car?
• Hi - Hi, there!
• Hmm - "He says he's doing it for our benefit." " Hmm, I'm still not convinced."
• Oh - Is that for me? Oh, you're so kind!
• Well - Well, what shall we do now?

Conjunctions

What are conjunctions?

A conjunction is a part of speech that joins two words, phrases or clauses together.
There are three types of conjunctions:

Coordinating Conjunctions	Correlative Conjunctions	Common Subordinating Conjunctions
and but or nor	either...or neither...nor not only...but also both...and whether...or	after before although though even though as much as as long as as soon as because since so that	in order that so if lest even if that unless until when where whether while

Coordinating conjunctions

Coordinating conjunctions, also called coordinators, are conjunctions that connect two or more equal items.
Examples:

• He plays tennis and soccer
• He works quickly but accurately
• You'd better do your homework, or you'll get a terrible grade.

Correlative conjunctions

Correlative conjunctions are used in pairs.They work in pairs to coordinate two items. Examples of correlative conjunctions include both...and..., either...or, not only... but also...
Examples:

• I didn't know that she can neither read nor write.
• You can either walk to school or take the bus.
• Both Sara and James are invited to the party.
• Whether you watch TV or do your homework is your decision.
• Not only are they noisy but they are also lazy.

Direct and Indirect Object

What is an object?

An object in grammar is a part of a sentence, and often part of the predicate. It refers to someone or something involved in the subject's "performance" of the verb. It is what the verb is being done to. As an example, the following sentence is given:

Subject	Verb	Object
Leila	wrote	the poem

• "Leila" is the subject, the doer or performer,
• "wrote" is a verb that refers to the action,
• "the poem" is the object involved in the action.

Transitive and intransitive verbs

A verb can be classified as transitive or intransitive according to whether it takes or doesn't take an object:

• If a verb takes objects, then it is a transitive verb.
  Example:
  They played soccer. → (The verb play takes ONE object 'soccer')
  They sent him a postcard. → (The verb send takes TWO objects 'him' and 'a postcard')
• If a verb doesn't take an object, then it is an intransitive verb.
  Example:
  She lies. → (The verb 'lie' doesn't take any object)
  The building collapsed. → (The verb 'collapse' doesn't take any object)

Types of objects

There are two types of objects: direct and indirect objects:

Direct object

A direct object answers the question "what?" or "whom?"
Examples:

• David repaired his car → his car is the direct object of the verb repaired. ( What did David repair?)
• He invited Mary to the party → Mary is the direct object of the verb invited. (Whom did he invite?)

Predicate

What is a predicate?

In traditional grammar, a sentence consists of two parts:

• a subject,
• a predicate which modifies the subject.

consider the following sentence:

• Bill likes soccer.

Bill is the subject and likes soccer acts as the predicate (a subsequent description of the subject which is headed with the verb likes.)
Predicates provide information about the subject, such as what the subject is doing or what the subject is like. It must contain a verb but may also contain other sentence elements. These elements may be objects (direct and indirect objects), adverbials...

Examples of predicates

• He laughs. (Predicate containing only a verb)
• She writes poems. (Direct object)
• They gave me a gift . (Indirect object and a direct object)
• He saw her in the hospital . (Adverbial)

When the subject and the predicate are connected with a linking verb, the predicate is either nominal, adjectival or adverbial complement:

Acronyms

What is an acronym?

An Acronym is a type of word formation process. It refers to a word formed from the initial letters of a name or by combining initial letters of a series of words.
Examples:

• NATO = North Atlantic Treaty Organization
• radar = radio detection and ranging
• AIDS = acquired immune deficiency syndrome
• Scuba = self-contained underwater breathing apparatus
• Laser = Light Amplification by Stimulated Emission of Radiation

Abbreviation

What is an abbreviation?

An abbreviation is a shortened word used mainly in writing to represent the complete form.

List of commonly used abbreviations

• A.D. = anno Domini, "in the year of the Lord"
• A.M. = Ante Meridiem, "before midday"
• cf. = confer, "bring together" and hence "compare"
• B.A. = Bachelor of Arts
• B.S. - Bachelor of Science
• M.A. = Magister Artium, Master of Arts
• e.g. = exempli gratia, 'for example'
• et al. = et alii, "and others", "and co-workers"
• etc. = et cetera, "and the others", "and other things", "and the rest"
• i.a. = inter alia, "among other things".
• ibid. = ibidem, "in the same place (book, etc.)"
• i.e. = id est, 'that is'
• id. = idem, "the same (man)"
• N.B. = nota bene, "note well"
• Ph. D. = Philosophiæ Doctor, "Teacher of Philosophy"
• P.M. = Post Meridiem, "after midday"
• S.O.S. = si opus sit, "if there is need", "if occasion require", "if necessary"
• vs. = versus, "against"

Blending

What are blends?

A blend, in morphology, is a word formed from parts of two or more words. In this sense blending is a process, among other processes, of creating new words.
Examples:

• brunch = breakfast + lunch
• Breathalyzer = breath + analyzer
• camcorder = camera + recorder
• emoticon = emote + icon
• motel = motor car + hotel
• Globish = global + English
• sitcom = situation + comedy
• smog = smoke + fog
• Spork = spoon + fork
• workaholic = work + alcoholic

Clipping

What is clipping?

Clipping refers to the reduction of a polysyllabic word by dropping a syllable or more from it.Clipping is also called truncation or shortening.
Examples:

• spec = speculation
• vet = veteran

Types of clipping

There are three types of clipping:

Back clipping

In this type the beginning is retained:
Examples:

• ad = advertisement
• cable = cablegram
• doc = doctor
• exam = examination
• fax = facsimile
• gas = gasoline
• gym = gymnastics, gymnasium
• memo = memorandum
• pub = public house
• pop = popular music

Fore-clipping

The final part is retained:
Examples:

• chute = parachute
• coon = raccoon
• gator = alligator
• phone = telephone

Middle clipping

The middle part is retained.
Example:

• flu = influenza
• fridge = refrigerator

Complex clipping

Clipping may also occur in compounds. In complex clipping, one part of the original compound most often remains intact. But sometimes both halves of a compound are clipped:

Contraction

What is contraction?

A contraction refers to a shortened form of a word, syllable, or word group, created by omission of internal letters which are replaced by an apostrophe.
Examples:

• I am = I'm
• He is = He's

Contractions should not be confused with:

1. Abbreviations which consist of a letter or group of letters taken from the word or phrase as in Dr for Doctor
2. Clipping which is the word formation process consisting in the reduction of a word to one of its parts as in spec for speculation.
3. Acronyms which is an abbreviation formed from the initial components in a phrase or a word (example: FBI, Benelux, radar)

There, Their, They're

What is the difference between there, their and they're?

The words there, their and they're are different and shouldn't be confused. The confusion may occur because the three words are homophones, pronounced in very similar ways.

Their

Their indicates possession. It is a third person plural possessive adjective that shows that a particular thing belongs to them.
Examples:

• This is their house.
• Have you met their son?
• Can you give me their phone number?

There

There may function as an adverb, an adjective, a pronoun, a noun or an interjection:

1. As an adverb there refers to a place (as opposed to the word here).
Examples:

• Please sit over there.
• I met him there twice.

Negation in English

Negative forms

Negation is the process that turns an affirmative statement into its opposite denial.
Example:
She is a nice girl - She is not a nice girl
Verbs in English are negated by placing the word not after an auxiliary or modal.
Examples:

• I am not from Germany
• I do not like playing tennis.
• She does not listen to classical music.
• I have not read this book yet.
• I did not go to Moscow.
• I had not had dinner when they came in.
• You should not sleep late.
• I cannot help you.
• I will not participate in that competition.

Why do tears taste salty?

Body fluids like sweat and tears are salty to taste and this has physiological, immunological and evolutionary significance. Tears are the secretions of lacrymal glands of eyes. These tears are classified into basal, reflex and psychic tears. The salinity and chemical composition of tears vary from type to type and situation to situation. Basal tears are responsible for keeping the cornea of eye moist. Reflex tears are produced during eye irritation. Psychic tears are produced during weeping. Tears contain greater quantities of water along with other organic and inorganic chemical components like mucin, lipids,lysozyme, lactoferrin, lipocalin,lacritin, sodium and potassium. The salinity of tears is attributed to the presence of salts of sodium and potassium. This salinity of tears along with the presence of enzymes like lysozyme is responsible for their antimicrobial activity. Basal tears have a salt content similar to blood plasma. The salinity of basal tears disturbs the osmotic balance of bacteria and keeps the cornea in a healthy microbial-free environment. The mineral content of tears also nourishes the tissues associated with eyes. Saline nature of tears also indicates our evolutionary descent from marine organisms. G.L.N.PRASAD , Head, Department of Zoology, Govt. UG & PG College, Anantapur, Andhra Pradesh

Genitive Case

Genitive case

Genitive case is is the grammatical case that marks a noun as modifying another noun. It often marks a noun as being the possessor of another noun; however, it can also indicate various other relationships than possession.
Examples:

• Janet’s long fingers, Janet’s jacket, Janet’s drink (relationship indicating possession)
• a wheel of cheese (a relationship indicating composition)
• the love of music (participation in an action)
• men of Rome (origin)
• the capital of the Republic (reference)
• man of honor(description)

Form of genitive case

Genitive case can be indicated by

1. adding 's after the noun (John's brother)
2. adding of before the noun (the end of the movie)

Intensifiers

What are intensifiers?

Words which are used to add force to the meaning of verbs, adjectives or other adverbs are called intensifiers.

Examples of intensifiers

These are examples of intensifiers:

• I strongly disagree.
• It's extremely hot in Africa.
• You play soccer very well.
• Do you really mean it.
• It's fairly interesting.
• It's quite calm here.
• He's pretty intelligent.
• These students are rather noisy.
• I so wanted to buy the dress.
• She writes poems too often.
• It's absolutely amazing.
• I am a little angry with her.

Too / Enough

Too and Enough

Too and enough indicate degree. They are used with adjectives.

• Too means more than what is needed.
• Enough means sufficient.

Examples

He is too old to play football with the kids.
Dave is intelligent enough to do the write thing.
You're not working fast enough
I don't have enough time.
He has too many friends.
She has got too much patience

Use of too and enough

1.Enough precedes adjectives and adverbs:

He isn't old enough to watch this program.
We're not walking quickly enough.

2.Enough may also precede nouns:

We have enough money . 
I have not got enough money to buy this computer.

3.Too comes before adjectives and adverbs:

It's too hot to wear that coat.
I was driving too fast.

Used to, be used to, get used to

Used to

Used to shows that:

• a particular thing always happened or was true in the past.
• But it no longer happens or is no longer true now:

Examples:

• David used to live in Madrid.
• She used to exercise every morning, but since she had that terrible accident she doesn't exercise anymore.
• Why don't you come and see me like you used to?

Forms of used to

Here are the interrogative, affirmative and negative forms of used to

• Did you use to exercise regularly?
• Yes, I used to go jogging nearly everyday.
• No, I didn't use to exercise on a regular basis.

Used to, be used to, get used to

1.Used to shows that a particular thing always happened or was true in the past (see examples above)
2.Be used to is used to say that something is normal, not unusual.
Examples:

• I'm used to living alone.
• Don't worry, John is used to driving for long hours. He has worked as a professional driver for 20 years.

Expressing a wish or a regret

Use of I wish / if only:

There are three distinct types of  I wish / if only  sentences:

1. Wish, wanting change for the present or future with the simple past.
2. Regret with the past perfect.
3. Complaints with would + verb.

Expressing a wish:

Form:

If only / I wish + simple past

Example:

If only I knew how to use a computer. (I don’t know how to use a computer and I would like to learn how to use it)

Use:

• To express a wish in the present or in the future.
• The simple past here is an unreal past.
• When you use the verb to be the form is “were”.
  Example:
  I wish I were a millionaire!

Expressing regret:

Form:

If only / I wish + past perfect

Example:

If only I had woken up early. (I didn't wake up early and I missed my bus.)

Use:

• To express a regret.
• The action is past.

Passive Voice

The passive vs the active voice:

The Active Voice	The Passive Voice
Most countries in Latin America speak Spanish.	Spanish is spoken in most countries in latin America.

Use of the passive voice:

1. Passive voice is used when the focus is on the action. It is not important or not known, however, who or what is performing the action.
   Example: "A letter was written."
   The focus, here, is on the fact that a letter was written. We don't know, however, who wrote it.
2. Sometimes a statement in passive is more polite than active voice, as the following example shows:
   Example: A vase was broken.
   Focus, here, is on the fact that a vase was broken, but we don't blame anyone. Compare this to: "You broke the vase."

Form of the passive voice:

Subject + the appropriate form of to be + Past Participle

NOTE: The appropriate form of to be = To be is put in the the tense of the active voice main verb.
When rewriting active sentences in passive voice, note the following:

• The object of the active sentence becomes the subject of the passive sentence.
• The form of the verb is the appropriate form of to be (the tense of the active voice main verb) + the past participle.
• The subject of the active sentence becomes the object of the passive sentence (or is dropped.)

Example:

Active	Nancy	makes	tea
	subject	verb	object
Passive	Tea	is made	(by Nancy)
	object becoming subject	verb	subject becoming object or is dropped

Examples of the passive voice:

Tense		Subject	Verb	Object
Simple Present	Active:	Nancy	makes	tea.
	Passive:	Tea	is made	by Nancy.
Present Progressive	Active:	Nancy	is making	tea.
	Passive:	Tea	is being made	by Nancy.
Simple Past	Active:	Nancy	made	tea.
	Passive:	Tea	was made	by Nancy.
Past Progressive	Active:	Nancy	was making	tea.
	Passive:	Tea	was being made	by Nancy.
Present Perfect	Active:	Nancy	has made	Tea.
	Passive:	Tea	has been made	by Nancy.
Past Perfect	Active:	Nancy	had made	tea.
	Passive:	Tea	had been made	by Nancy.
Future simple	Active:	Nancy	will make	tea.
	Passive:	Tea	will be made	by Nancy.
Future perfect	Active:	Nancy	will have made	tea.
	Passive:	Tea	will have been made	by Nancy.
Conditional	Active:	Nancy	would make	tea.
	Passive:	Tea	would be made	by Nancy.
Modals	Active:	Nancy	can make	tea.
	Passive:	Tea	can be made	by Nancy.

Passive voice sentences with two Objects:

Rewriting an active sentence with two objects in passive voice means that one of the two objects becomes the subject, the other one remains an object. Which object to transform into a subject depends on what you want to put the focus on.

Active/Passive	Subject	Verb	Object 1	Object 2
Active:	Nancy	offered	a flower	to me.
Passive:	A flower	was offered	to me	by Nancy.
Passive:	I	was offered	a flower	by Nancy.

Impersonal Passive:

Study these examples:

• They say that the planet is in danger.
• It is said that the planet is in danger.