We use the present perfect when we want to look back from the present to the past.

We can use it to look back on the recent past.

• I've broken my watch so I don't know what time it is.
• They have cancelled the meeting.
• She's taken my copy. I don't have one.
• The sales team has doubled its turnover.

When we look back on the recent past, we often use the words 'just' 'already' or the word 'yet' (in negatives and questions only).

• We've already talked about that.
• She hasn't arrived yet.
• I've just done it.
• They've already met.
• They don't know yet.
• Have you spoken to him yet?
• Have they got back to you yet?

It can also be used to look back on the more distant past.

• We've been to Singapore a lot over the last few years.
• She's done this type of project many times before.
• We've mentioned it to them on several occasions over the last six months.
• They've often talked about it in the past.

When we look back on the more distant past, we often use the words 'ever' (in questions) and 'never'.

• Have you ever been to Argentina?
• Has he ever talked to you about the problem?
• I've never met Jim and Sally.
• We've never considered investing in Mexico.

How do we make the Present Perfect Tense?

The structure of the present perfect tense is:

subject	+	auxiliary verb	+	main verb
		have		past participle

Here are some examples of the present perfect tense:

	subject	auxiliary verb		main verb
+	I	have		seen	ET.
+	You	have		eaten	mine.
-	She	has	not	been	to Rome.
-	We	have	not	played	football.
?	Have	you		finished?
?	Have	they		done	it?

How do we use the Present Perfect Tense?

This tense is called the present perfect tense. There is always a connection with the past and with the present. There are basically three uses for the present perfect tense:

1. experience
2. change
3. continuing situation

1. Present perfect tense for experience

We often use the present perfect tense to talk about experience from the past. We are not interested in when you did something. We only want to know if you did it:

I have seen ET. He has lived in Bangkok. Have you been there? We have never eaten caviar.
past	present	future
!!!
The action or state was in the past.	In my head, I have a memory now.

Connection with past: the event was in the past.
Connection with present: in my head, now, I have a memory of the event; I know something about the event; I have experience of it.

2. Present perfect tense for change

We also use the present perfect tense to talk about a change or new information:

I have bought a car.
past	present	future
-	+
Last week I didn't have a car.	Now I have a car.

John has broken his leg.
past	present	future
+	-
Yesterday John had a good leg.	Now he has a bad leg.

Has the price gone up?
past	present	future
+	-
Was the price $1.50 yesterday?	Is the price $1.70 today?

The police have arrested the killer.
past	present	future
-	+
Yesterday the killer was free.	Now he is in prison.

Connection with past: the past is the opposite of the present.
Connection with present: the present is the opposite of the past.

3. Present perfect tense for continuing situation

We often use the present perfect tense to talk about a continuing situation. This is a state that started in the past and continues in the present (and will probably continue into the future). This is a state (not an action). We usually use for or since with this structure.

I have worked here since June. He has been ill for 2 days. How long have you known Tara?
past	present	future
The situation started in the past.	It continues up to now.	(It will probably continue into the future.)

Connection with past: the situation started in the past.
Connection with present: the situation continues in the present.

For & Since with Present Perfect Tense

We often use for and since with the present perfect tense.

• We use for to talk about a period of time - 5 minutes, 2 weeks, 6 years.
• We use since to talk about a point in past time - 9 o'clock, 1st January, Monday.

for	since
a period of time	a point in past time
	x------------
20 minutes	6.15pm
three days	Monday
6 months	January
4 years	1994
2 centuries	1800
a long time	I left school
ever	the beginning of time
etc	etc

Here are some examples:

• I have been here for 20 minutes.
• I have been here since 9 o'clock.
• John hasn't called for 6 months.
• John hasn't called since February.
• He has worked in New York for a long time.
• He has worked in New York since he left school.

Source:
http://www.englishclub.com/

The passive voice is less usual than the active voice. The active voice is the "normal" voice. But sometimes we need the passive voice. In this lesson we look at how to construct the passive voice, when to use it and how to conjugate it.

Construction of the Passive Voice

The structure of the passive voice is very simple:

subject + auxiliary verb (be) + main verb (past participle)

The main verb is always in its past participle form.

Look at these examples:

subject	auxiliary verb (to be)		main verb (past participle)
Water	is		drunk	by everyone.
100 people	are		employed	by this company.
I	am		paid	in euro.
We	are	not	paid	in dollars.
Are	they		paid	in yen?

Use of the Passive Voice

We use the passive when:

• we want to make the active object more important
• we do not know the active subject

	subject	verb	object
give importance to active object (President Kennedy)	President Kennedy	was killed	by Lee Harvey Oswald.
active subject unknown	My wallet	has been stolen.	?

Note that we always use by to introduce the passive object (Fish are eaten by cats).

Conjugation for the Passive Voice

We can form the passive in any tense. In fact, conjugation of verbs in the passive tense is rather easy, as the main verb is always in past participle form and the auxiliary verb is always be. To form the required tense, we conjugate the auxiliary verb. So, for example:

• present simple: It is made
• present continuous: It is being made
• present perfect: It has been made

Here are some examples with most of the possible tenses:

infinitive		to be washed
simple	present	It is washed.
	past	It was washed.
	future	It will be washed.
	conditional	It would be washed.
continuous	present	It is being washed.
	past	It was being washed.
	future	It will be being washed.
	conditional	It would be being washed.
perfect simple	present	It has been washed.
	past	It had been washed.
	future	It will have been washed.
	conditional	It would have been washed.
perfect continuous	present	It has been being washed.
	past	It had been being washed.
	future	It will have been being washed.
	conditional	It would have been being washed.

Sources:

http://www.englishclub.com/

Countable Nouns

Countable nouns are easy to recognize. They are things that we can count. For example: "pen". We can count pens. We can have one, two, three or more pens. Here are some more countable nouns:

• dog, cat, animal, man, person
• bottle, box, litre
• coin, note, dollar
• cup, plate, fork
• table, chair, suitcase, bag

Countable nouns can be singular or plural:

• My dog is playing.
• My dogs are hungry.

We can use the indefinite article a/an with countable nouns:

• A dog is an animal.

When a countable noun is singular, we must use a word like a/the/my/this with it:

• I want an orange. (not I want orange.)
• Where is my bottle? (not Where is bottle?)

When a countable noun is plural, we can use it alone:

• I like oranges.
• Bottles can break.

We can use some and any with countable nouns:

• I've got some dollars.
• Have you got any pens?

We can use a few and many with countable nouns:

• I've got a few dollars.
• I haven't got many pens.

Uncountable Nouns

Uncountable nouns are substances, concepts etc that we cannot divide into separate elements. We cannot "count" them. For example, we cannot count "milk". We can count "bottles of milk" or "litres of milk", but we cannot count "milk" itself. Here are some more uncountable nouns:

• music, art, love, happiness
• advice, information, news
• furniture, luggage
• rice, sugar, butter, water
• electricity, gas, power
• money, currency

We usually treat uncountable nouns as singular. We use a singular verb. For example:

• This news is very important.
• Your luggage looks heavy.

We do not usually use the indefinite article a/an with uncountable nouns. We cannot say "an information" or "a music". But we can say a something of:

• a piece of news
• a bottle of water
• a grain of rice

We can use some and any with uncountable nouns:

• I've got some money.
• Have you got any rice?

We can use a little and much with uncountable nouns:

• I've got a little money.
• I haven't got much rice.

Sources:
http://www.englishclub.com/

What are Nouns?
The simple definition is: a person, place or thing. Here are some examples:

* person: man, woman, teacher, John, Mary
* place: home, office, town, countryside, America
* thing: table, car, banana, money, music, love, dog, monkey

The problem with this definition is that it does not explain why "love" is a noun but can also be a verb.

Another (more complicated) way of recognizing a noun is by its:

1. Ending
2. Position
3. Function

1. Noun Ending

There are certain word endings that show that a word is a noun, for example:

* -ity > nationality
* -ment > appointment
* -ness > happiness
* -ation > relation
* -hood > childhood

But this is not true for the word endings of all nouns. For example, the noun "spoonful" ends in -ful, but the adjective "careful" also ends in -ful.

2. Position in Sentence

We can often recognise a noun by its position in the sentence.

Nouns often come after a determiner (a determiner is a word like a, an, the, this, my, such):

* a relief
* an afternoon
* the doctor
* this word
* my house
* such stupidity

Nouns often come after one or more adjectives:

* a great relief
* a peaceful afternoon
* the tall, Indian doctor
* this difficult word
* my brown and white house
* such crass stupidity

3. Function in a Sentence

Nouns have certain functions (jobs) in a sentence, for example:

* subject of verb: Doctors work hard.
* object of verb: He likes coffee.
* subject and object of verb: Teachers teach students.

But the subject or object of a sentence is not always a noun. It could be a pronoun or a phrase. In the sentence "My doctor works hard", the noun is "doctor" but the subject is "My doctor".

Sources:
http://www.englishclub.com/

Prepositional verbs are a group of multi-word verbs made from a verb plus another word or words. Many people refer to all multi-word verbs as phrasal verbs. On these pages we make a distinction between three types of multi-word verbs: prepositional verbs, phrasal verbs and phrasal-prepositional verbs. On this page we look at prepositional verbs.

Prepositional verbs are made of:

verb + preposition

Because a preposition always has an object, all prepositional verbs have direct objects. Here are some examples of prepositional verbs:

prepositional verbs	meaning	examples
			direct object
believe in	have faith in the existence of	I believe in	God.
look after	take care of	He is looking after	the dog.
talk about	discuss	Did you talk about	me?
wait for	await	John is waiting for	Mary.

Prepositional verbs cannot be separated. That means that we cannot put the direct object between the two parts. For example, we must say "look after the baby". We cannot say "look the baby after":

prepositional verbs are inseparable		Who is looking after the baby?	This is possible.
		Who is looking the baby after?	This is not possible.

Sources:
http://www.englishclub.com/

Phrasal verbs are a group of multi-word verbs made from a verb plus another word or words. Many people refer to all multi-word verbs as phrasal verbs. On these pages we make a distinction between three types of multi-word verbs: prepositional verbs, phrasal verbs and phrasal-prepositional verbs. On this page we look at phrasal verbs proper.

Phrasal verbs are made of:

verb + adverb

Phrasal verbs can be:

• intransitive (no direct object)
• transitive (direct object)

Here are some examples of phrasal verbs:

	phrasal verbs	meaning	examples
				direct object
intransitive phrasal verbs	get up	rise from bed	I don't like to get up.
	break down	cease to function	He was late because his car broke down.
transitive phrasal verbs	put off	postpone	We will have to put off	the meeting.
	turn down	refuse	They turned down	my offer.

Separable Phrasal Verbs

When phrasal verbs are transitive (that is, they have a direct object), we can usually separate the two parts. For example, "turn down" is a separable phrasal verb. We can say: "turn downturn my offer down". Look at this table: my offer" or "

transitive phrasal verbs are separable		They	turned		down	my offer.
		They	turned	my offer	down.

However, if the direct object is a pronoun, we have no choice. We must separate the phrasal verb and insert the pronoun between the two parts. Look at this example with the separable phrasal verb "switch on":

direct object pronouns must go between the two parts of transitive phrasal verbs		John	switched		on	the radio.	These are all possible.
		John	switched	the radio	on.
		John	switched	it	on.
		John	switched		on	it.	This is not possible.

Sources:
http://www.englishclub.com/
http://www.edufind.com/

The future continuous refers to an unfinished action or event that will be in progress at a time later than now. It is used:

• to project ourselves into the future and see something happening: This time next week I will be sun-bathing in Bali.

• to refer to actions/events that will happen in the normal course of events: I'll be seeing Jim at the conference next week.

• in the interrogative form, especially with 'you', to distinguish between a simple request for information and an invitation: Will you be coming to the party tonight? (= request for information) Will you come to the party? (= invitation)

• to predict or guess about someone's actions or feelings, now or in the future: You'll be feeling tired after that long walk, I expect.

More examples:

a. events in progress in the future:
When you are in Australia will you be staying with friends?
This time next week you will be working in your new job.
At four thirty on Tuesday afternoon I will be signing the contract.

b. events/actions in normal course of events:
I'll be going into town this afternoon, is there anything you want from the shops?
Will you be using the car tomorrow? - No, you can take it.
I'll be seeing Jane this evening - I'll give her the message.

c. asking for information:
Will you be bringing your friend to the pub tonight?
Will Jim be coming with us?

d. predicting or guessing:
You'll be feeling thirsty after working in the sun.
He'll be coming to the meeting, I expect.
You'll be missing the sunshine now you're back in England.

How do we make the Future Continuous Tense?

The structure of the future continuous tense is:

subject	+	auxiliary verb WILL	+	auxiliary verb BE	+	main verb
		invariable		invariable		present participle
		will		be		base + ing

For negative sentences in the future continuous tense, we insert not between will and be. For question sentences, we exchange the subject and will. Look at these example sentences with the future continuous tense:

	subject	auxiliary verb		auxiliary verb	main verb
+	I	will		be	working	at 10am.
+	You	will		be	lying	on a beach tomorrow.
-	She	will	not	be	using	the car.
-	We	will	not	be	having	dinner at home.
?	Will	you		be	playing	football?
?	Will	they		be	watching	TV?

When we use the future continuous tense in speaking, we often contract the subject and will:

I will	I'll
you will	you'll
he will she will it will	he'll she'll it'll
we will	we'll
they will	they'll

For spoken negative sentences in the future continuous tense, we contract with won't, like this:

I will not	I won't
you will not	you won't
he will not she will not it will not	he won't she won't it won't
we will not	we won't
they will not	they won't

How do we use the Future Continuous Tense?

The future continuous tense expresses action at a particular moment in the future. The action will start before that moment but it will not have finished at that moment. For example, tomorrow I will start work at 2pm and stop work at 6pm:

At 4pm tomorrow, I will be working.
past	present	future
4pm
		At 4pm, I will be in the middle of working.

When we use the future continuous tense, our listener usually knows or understands what time we are talking about. Look at these examples:

• I will be playing tennis at 10am tomorrow.
• They won't be watching TV at 9pm tonight.
• What will you be doing at 10pm tonight?
• What will you be doing when I arrive?
• She will not be sleeping when you telephone her.
• We 'll be having dinner when the film starts.
• Take your umbrella. It will be raining when you return.

The past continuous describes actions or events in a time before now, which began in the past and was still going on at the time of speaking. In other words, it expresses an unfinished or incomplete action in the past.

It is used:

• often, to describe the background in a story written in the past tense, e.g. "The sun was shining and the birds were singing as the elephant came out of the jungle. The other animals were relaxing in the shade of the trees, but the elephant moved very quickly. She was looking for her baby, and she didn't notice the hunter who was watching her through his binoculars. When the shot rang out, she was running towards the river..."

• to describe an unfinished action that was interrupted by another event or action: "I was having a beautiful dream when the alarm clock rang."

• to express a change of mind: e.g. "I was going to spend the day at the beach but I've decided to go on an excursion instead."

• with 'wonder', to make a very polite request: e.g. "I was wondering if you could baby-sit for me tonight."

More examples:

• They were waiting for the bus when the accident happened.
• Caroline was skiing when she broke her leg.
• When we arrived he was having a bath.
• When the fire started I was watching television.

How do we make the Past Continuous Tense?

The structure of the past continuous tense is:

subject	+	auxiliary verb BE	+	main verb
		conjugated in simple past tense		present participle
		was were		base + ing

For negative sentences in the past continuous tense, we insert not between the auxiliary verb and main verb. For question sentences, we exchange the subject and auxiliary verb. Look at these example sentences with the past continuous tense:

	subject	auxiliary verb		main verb
+	I	was		watching	TV.
+	You	were		working	hard.
-	He, she, it	was	not	helping	Mary.
-	We	were	not	joking.
?	Were	you		being	silly?
?	Were	they		playing	football?

How do we use the Past Continuous Tense?

The past continuous tense expresses action at a particular moment in the past. The action started before that moment but has not finished at that moment.

For example, yesterday I watched a film on TV. The film started at 7pm and finished at 9pm.

At 8pm yesterday, I was watching TV.
past	present	future
8pm
At 8pm, I was in the middle of watching TV.

When we use the past continuous tense, our listener usually knows or understands what time we are talking about. Look at these examples:

• I was working at 10pm last night.
• They were not playing football at 9am this morning.
• What were you doing at 10pm last night?
• What were you doing when he arrived?
• She was cooking when I telephoned her.
• We were having dinner when it started to rain.
• Ram went home early because it was snowing.

Past Continuous Tense + Simple Past Tense

We often use the past continuous tense with the simple past tense. We use the past continuous tense to express a long action. And we use the simple past tense to express a short action that happens in the middle of the long action. We can join the two ideas with when or while.

In the following example, we have two actions:

1. long action (watching TV), expressed with past continuous tense
2. short action (telephoned), expressed with simple past tense

past	present	future
Long action.
I was watching TV at 8pm. 8pm You telephoned at 8pm.
Short action.

We can join these two actions with when:

• I was watching TV when you telephoned.

(Notice that "when you telephoned" is also a way of defining the time [8pm].)

We use:

• when + short action (simple past tense)
• while + long action (past continuous tense)

There are four basic combinations:

	I was walking past the car	when	it exploded.
When	the car exploded		I was walking past it.
	The car exploded	while	I was walking past it.
While	I was walking past the car		it exploded.

Notice that the long action and short action are relative.

• "Watching TV" took a few hours. "Telephoned" took a few seconds.
• "Walking past the car" took a few seconds. "Exploded" took a few milliseconds.

Sources:
http://www.englishclub.com/
http://www.edufind.com/

The present participle of most verbs has the form base+ing and is used in the following ways:

a. as part of the continuous form of a verb
(See continuous tenses in Present Continuous Tense)

Example:

I am working,
he was singing,
they have been walking.

b. after verbs of movement/position in the pattern: verb + present participle

Example:

• She went shopping
• He lay looking up at the clouds
• She came running towards me

This construction is particularly useful with the verb 'to go', as in these common expressions :

to go shopping to go ski-ing to go fishing to go surfing

to go walking to go swimming to go running to go dancing

c. after verbs of perception in the pattern:
verb + object + present participle

Example:

I heard someone singing.
He saw his friend walking along the road.
I can smell something burning!

NOTE: There is a difference in meaning when such a sentence contains a zero-infinitive rather than a participle. The infinitive refers to a complete action, but the participle refers to an incomplete action, or part of an action.

Compare:

• I heard Joanna singing (= she had started before I heard her, and probably went on afterwards)
• I heard Joanna sing (= I heard her complete performance)

d. as an adjective

Examples:

amazing, worrying, exciting, boring.

• It was an amazing film.
• It's a bit worrying when the police stop you
• Dark billowing clouds often precede a storm.
• Racing cars can go as fast as 400kph.
• He was trapped inside the burning house.
• Many of his paintings depict the setting sun.

e. with the verbs spend and waste, in the pattern:
verb + time/money expression + present participle

Example:

• My boss spends two hours a day travelling to work.
• Don't waste time playing computer games!
• They've spent the whole day shopping.

f. with the verbs catch and find, in the pattern:
verb + object + present participle:

With catch, the participle always refers to an action which causes annoyance or anger:

• If I catch you stealing my apples again, there'll be trouble!
• Don't let him catch you reading his letters.

This is not the case with find, which is unemotional:

• We found some money lying on the ground.
• They found their mother sitting in the garden.

g. to replace a sentence or part of a sentence:

When two actions occur at the same time, and are done by the same person or thing, we can use a present participle to describe one of them:

• They went out into the snow. They laughed as they went. They went laughing out into the snow.
  
  
• He whistled to himself. He walked down the road. Whistling to himself, he walked down the road.

When one action follows very quickly after another done by the same person or thing, we can express the first action with a present participle:

• He put on his coat and left the house. Putting on his coat, he left the house.
  
  
• She dropped the gun and put her hands in the air. Dropping the gun, she put her hands in the air.

The present participle can be used instead of a phrase starting as, since, because, and it explains the cause or reason for an action:

• Feeling hungry, he went into the kitchen and opened the fridge.
  (= because he felt hungry...)
• Being poor, he didn't spend much on clothes.
• Knowing that his mother was coming, he cleaned the flat.

Source: http://www.edufind.com/