- The road may be blocked due to the procession. (Factual possibility.)
- Any road can be blocked. (Theoretical possibility - It is possible to block any road.)
- There may be a strike next week. (It is possible that there will be a strike next week.)
- Strikes can happen any time. (It is possible for strikes to happen any time.)
- If you drive carelessly, you may have an accident. (Factual possibility)
- Accidents can happen any time. (Theoretical possibility)
When we talk about possibility, could often means the same as may or might.
- You may/might/could be right.
May not and Cannot
May not suggests improbability. Cannot suggests impossibility.
- We may not go camping this summer. (= It is possible that we may not go camping.)
- We cannot go camping this summer. (= It is not possible for us to go camping this summer.)
May is a modal auxiliary verb. There is no –s in the third person singular.
- She may be here soon. (NOT She mays …)
May is followed by an infinitive without to.
- You may be right. (NOT You may to be right.)
- He may come.
Questions and negatives are made without do.
- May I come in, please? (NOT Do I may come …)
- He may not come. (NOT He do not may come.)
May does not have infinitives (to may) or participles (maying, mayed). When necessary, we use other words.
May is used to talk about possibility, and to ask for and give permission.
- It may rain this afternoon.
- May I play carroms, mummy?
- Yes, you may.
May is used to talk about the chances of something happening.
- I think it is going to rain. You may be right.
- There may be a strike next week.
- Where is John? He may be out shopping.
May well is used to suggest a strong possibility.
- I think it is going to rain. You may well be right.
May is not normally used in direct questions about probability.
- Are they likely to help us? (BUT NOT May they help us?)
But note that may is possible in indirect questions about probability.
- May we not be making a big mistake?
May + perfect infinitive
The structure may + perfect Infinitive (have + past participle) can be used to say that it is possible that something happened or was true in the past.
- Alice is very late. She may have missed her train. (= It is possible that she missed her train.)
May + perfect infinitive can also refer to the present or future.
- I will try phoning him, but he may have gone out by now.
May can be used to ask for permission. It is more formal than can and could.
- May I come in?
May is used to give permission; may not is used to refuse permission and to forbid.
- May I come in? Yes, you may.
- May I have a look at your papers? No, I am afraid you may not.
Must not is also used to forbid. It is stronger than may not.
- Students must not use the staff car park.
May and might are not normally used to talk about permission which has already been given or refused, about freedom which people already have, or about rules and laws. Instead, we use can, could or be allowed.
- Can you/Are you allowed to park on both sides of the road here? (More natural than May you allowed …)
- When we were children, we could watch TV whenever we wanted to. (NOT …we might watch TV …)
May in wishes and hopes
May is used in formal expressions of wishes and hopes. May often comes at the beginning of the sentence.
- May God bless you!
- May you both be very happy!
- May the devil take him!
- May you prosper in all that you do!
Could is an auxiliary verb, a modal auxiliary verb. We use could to:
- talk about past possibility or ability
- make requests
Structure of Could
subject + could + main verb
The main verb is always the bare infinitive (infinitive without "to").
| ||subject||auxiliary verb||main verb|
- Could is invariable. There is only one form of could.
- The main verb is always the bare infinitive.
To talk about past ability in general
Could is often used to say that somebody was able to do something in the past.
- My father could walk without help when he was 95.
- She could read when she was 3.
- When we were children, we could watch TV whenever we wanted to.
- In my younger days, I could run four miles at a stretch.
Note that could refers to the past only when the context makes the time clear.
Could not (also couldn't) shows past inability.
- I could not understand a word, but I kept smiling.
- She spoke in such a low voice that most of us could not hear her.
- We found that we couldn't depend on our guide.
Could is used to talk about past ability in general. We do not normally use could to say that somebody managed to do something on one occasion. But with certain verbs like see, hear, taste, feel, smell, understand, remember etc., could can be used for particular occasions as well.
- Suddenly I could hear a loud noise.
- I could smell something burning.
As the past equivalent of can
Could is the past equivalent of can in indirect speech.
- He said, "I can drive."
- He said that he could drive.
- She said, "I can't climb up the hill."
- She said that she could not climb up the hill.
To make polite requests or offers
Could is often used to make a request or offer sound more polite.
- Could I have a glass of water, please?
- Could you help me with these bags?
To express possibility or uncertainty
Could can mean would be able to.
- You could get a better job if you spoke English. (=You would be able to get a better job if you spoke English.)
- You could do it if you tried hard. (=You would be able to do it…)
- If only I had some working capital, I could start a new business. (=…I would be able to start a new business.)
Could have + past participle
The structure could have + past participle can be used to criticize people for not doing things. It can also be used to talk about past events that did not happen.
- I have been waiting since morning - you could have said that you weren't coming.
- Why did you drive so carelessly? You could have killed yourself.
These two varieties of English are very similar that most American and British speakers can understand each other without great difficulty. There are, however, a few differences of grammar, vocabulary and spelling. The following guide is meant to point out the principal differences between American English (AE) and British English (BE).
Differences in Grammar
Use of the Present Perfect
The British use the present perfect to talk about a past action which has an effect on the present moment. In American English both simple past and present perfect are possible in such situations.
I have lost my pen. Can you borrow me yours? (BE)
I lost my pen. OR I have lost my pen. (AE)
He has gone home. (BE)
He went home. OR He has gone home. (AE)
Other differences include the use of already, just and yet. The British use the present perfect with these adverbs of indefinite time. In American English simple past and present perfect are both possible.
He has just gone home. (BE)
He just went home. OR He has just gone home. (AE)
I have already seen this movie. (BE)
I have already seen this movie. OR I already saw this movie. (AE)
She hasn't come yet. (BE)
She hasn't come yet. OR She didn't come yet. (AE)
The British normally use have got to show possession. In American English have (in the structure do you have) and have got are both possible.
Have you got a car? (BE)
Do you have a car? OR Have you got a car? (AE)
Use of the verb Get
In British English the past participle of get is got. In American English the past participle of get is gotten, except when have got means have.
He has got a prize. (BE)
He has gotten a prize. (AE)
I have got two sisters. (BE)
I have got two sisters. (=I have two sisters.)(AE)
In British English it is fairly common to use shall with the first person to talk about the future. Americans rarely use shall.
I shall/will never forget this favour. (BE)
I will never forget this favour. (AE)
In offers the British use shall. Americans use should.
Shall I help you with the homework? (BE)
Should I help you with the homework? (AE)
In British English needn't and don't need to are both possible. Americans normally use don't need to.
You needn't reserve seats. OR You don't need to reserve seats. (BE)
You don't need to reserve seats. (AE)
Use of the Subjunctive
In American English it is particularly common to use subjunctive after words like essential, vital, important, suggest, insist, demand, recommend, ask, advice etc. (Subjunctive is a special kind of present tense which has no -s in the third person singular. It is commonly used in that clauses after words which express the idea that something is important or desirable.) In British English the subjunctive is formal and unusual. British people normally use should + Infinitive or ordinary present and past tenses.
It is essential that every child get an opportunity to learn. (AE)
It is essential that every child gets an opportunity to learn. (BE)
It is important that he be told. (AE)
It is important that he should be told. (BE)
She suggested that I see a doctor. (AE)
She suggested that I should see a doctor. (BE)
She insisted that I go with her. (AE)
She insisted that I should go with her. (BE)
Collective nouns like jury, team, family, government etc., can take both singular and plural verbs in British English. In American English they normally take a singular verb.
The committee meets/meet tomorrow. (BE)
The committee meets tomorrow. (AE)
The team is/are going to lose. (BE)
The team is going to lose. (AE)
Auxiliary verb + do
In British English it is common to use do as a substitute verb after an auxiliary verb. Americans do not normally use do after an auxiliary verb.
May I have a look at your papers? You may (do) (BE)
You may. (AE)
'Have you finished your homework?' 'I have (done).' (BE)
'I have.' (AE)
As if/ like
In American English it is common to use like instead of as if/ as though. This is not correct in British English.
He talks as if he knew everything. (BE)
He talks like/as if he knew everything. (AE)
In American English it is also common to use were instead of was in unreal comparisons.
He talks as if he was rich. (BE)
He talks as if he were rich. (AE)
The indefinite pronoun One
Americans normally use he/she, him/her, his/her to refer back to one. In British English one is used throughout the sentence.
One must love one's country. (BE)
One must love his/her country. (AE)
Mid position adverbs
In American English mid position adverbs are placed before auxiliary verbs and other verbs. In British English they are placed after auxiliary verbs and before other verbs.
He has probably arrived now. (BE)
He probably has arrived now. (AE)
I am seldom late for work. (BE)
I seldom am late for work. (AE)
Can is an auxiliary verb, a modal auxiliary verb. We use can to:
- talk about possibility and ability
- make requests
- ask for or give permission
Structure of Can
subject + can + main verb
The main verb is always the bare infinitive (infinitive without "to").
|subject||auxiliary verb||main verb|| |
- Can is invariable. There is only one form of can.
- The main verb is always the bare infinitive.
Can is used to talk about ability and possibility, to ask for and give permission, and to make requests and offers.
To talk about theoretical possibility
We can use can to talk about ‘theoretical’ possibility – to say that situations and events are possible theoretically.
- Glass can be blown. (It is theoretically possible to blow glass.)
- Wars can break out any time. (It is theoretically possible for wars to break out any time.)
- Smoking can cause cancer.
- Noise can be quite a problem when you are living in a city.
Note that we do not use can to talk about future probability – to say that something will happen in future. We express this idea with may or might.
- It may rain this evening. (NOT It can rain …)
- There may be a strike next week. (NOT There can be a strike …)
- I may get a job soon.
Note that might expresses a less definite possibility than may. Could is also used in the same sense.
- It could rain this evening. (= It might rain this evening.)
To talk about logical possibility
Can is often used in questions and negatives to talk about the logical possibility that something is true.
- There is the doorbell? Who can it be?
With this meaning can is not possible in affirmative clauses. Instead, we use could, may or might.
- Where is John? He could/may/might be in the garden. (NOT He can be in the garden.)
To talk about ability
We can use can to talk about present or general ability – to say that we are capable of doing something.
- I can speak 10 languages.
- She can cook well.
- Can you knit?
- If you are not satisfied with this product, you can send it back.
Note that be able to can often be used with similar meanings.
- He is able to support her. (= He can support her.)
- They were able to catch the thief. (= They could catch the thief.)
Cannot (also can’t) shows inability.
- I can speak French, but I cannot write it.
- Most people cannot read traffic signals.
- I can't drive.
We do not use can to talk about future ability. Instead, we use will be able to or other words.
- Someday scientists will be able to find a cure for cancer. (NOT Someday scientists will can find a cure for cancer.)
To ask for or give permission
Can is sometimes used to ask for and give permission. Some people, however, think that maycan. is more correct than
- Can I use your car, John?
- Can we park over there?
- You can go out and play after you have finished your homework.
- You can park on either side of the road here.
- Can I go to the movies, mom?
Note that we can also use could to ask for permission. It is a more polite form of can .
- Could I speak to Mr. John, please?
- Could I have look at your newspaper?
Cannot is used to refuse permission.
- Can I go to the movies, mom? No, you can’t.
To make requests and offers
Can is used in polite requests and offers of help.
- Can you turn that music down? I am trying to work.
- Can you get me a cup of coffee?
- Can I help you with those bags?
Note that Could is a more polite way of making requests and offers.
- Could you help me with my homework?
- Could you lend me some money?
An auxiliary verb is one which helps other verbs to make tenses, passive forms etc. There are two groups - primary auxiliaries and modal auxiliaries.
The verbs will, would, shall, should, can, could, may, might, must, ought, dare and need are usually called modal auxiliaries. They are used with other verbs to express actions, events or situations that exist only as conceptions of the mind - permissions, possibilities, certainty, ability, wishes, obligations etc. They may also express simple futurity.
- I can swim.
- She will come.
- I must go now.
- Should I call them?
- She might come.
Modal auxiliaries have three common characteristics.
1. They are never used alone. A principal verb is either present or implied.
- I can fly an aeroplane.
- He should behave.
- Will you go? Yes, I will (go).
2. Modal auxiliaries have no –s in the third person singular.
- I can swim.
- She can swim. (NOT She cans …)
- I may pass.
- He may pass.
- They may pass.
3. Modal auxiliaries do not have infinitives (to may, to shall etc.) or participles (maying, shalling, shalled etc.). You cannot say to shall, to must or to may.
e.g. She had heard the news before I saw her.
I had finished my work by the time the clock struck twelve.
In the preceding examples, the verbs had heard and had finished are in the Past Perfect tense, and the verbs saw and struck are in the Simple Past. The use of the Past Perfect tense indicates that the actions of hearing the news and finishing the work were already completed by the time the actions expressed by the verbs in the Simple Past took place.
The structure of the past perfect tense is:
|subject||+||auxiliary verb HAVE||+||main verb|
|conjugated in simple past tense||past participle|
For negative sentences in the past perfect 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 perfect tense:
|subject||auxiliary verb||main verb|
When speaking with the past perfect tense, we often contract the subject and auxiliary verb:
The past perfect tense expresses action in the past before another action in the past. This is the past in the past. For example:
- The train left at 9am. We arrived at 9.15am. When we arrived, the train had left.
|The train had left when we arrived.|
|Train leaves in past at 9am.|
|We arrive in past at 9.15am.|
Look at some more examples:
- I wasn't hungry. I had just eaten.
- They were hungry. They had not eaten for five hours.
- I didn't know who he was. I had never seen him before.
- "Mary wasn't at home when I arrived."
"Really? Where had she gone?"
You can sometimes think of the past perfect tense like the present perfect tense, but instead of the time being now the time is past.
|past perfect tense||present perfect tense|
For example, imagine that you arrive at the station at 9.15am. The stationmaster says to you:
- "You are too late. The train has left."
Later, you tell your friends:
- "We were too late. The train had left."
We often use the past perfect tense in reported speech after verbs like said, told, asked, thought, wondered:
Look at these examples:
- He told us that the train had left.
- I thought I had met her before, but I was wrong.
- He explained that he had closed the window because of the rain.
- I wondered if I had been there before.
- I asked them why they had not finished.
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|| |
|?||Have||you|| ||finished?|| |
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:
- 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.
|The action or state was in the past.||In my head, I have a memory now.|
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.|
|Last week I didn't have a car.||Now I have a car.|
|John has broken his leg.|
|Yesterday John had a good leg.||Now he has a bad leg.|
|Has the price gone up?|
|Was the price $1.50 yesterday?||Is the price $1.70 today?|
|The police have arrested the killer.|
|Yesterday the killer was free.||Now he is in prison.|
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?
|The situation started in the past.||It continues up to now.||(It will probably continue into the future.)|
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.
|a period of time||a point in past time|
|a long time||I left school|
|ever||the beginning of time|
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.
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)|
|100 people||are||employed||by this company.|
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
|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.|