MODALSWOULD as a kind of past form of WILL:

When I was a child, I thought I would be an astronaut.

as a polite request:Would you help me with my bags?

We use it in certain IF clauses:

If I was a bird, I would fly high in the sky

SHOULD (and OUGHT TO) to make a suggestion or point out a good choice:

You should give her flowers and apologize.

to show high probability or certainty:Its an old pen, but it should still work.

MUST (and HAVE TO) to show obligation:

You must submit the form by 2:30 today

to show certainty:That guy must be crazy! Hes eating his hat.

CAN shows ability:

Superman can fly. as a polite request.

Can you help me to carry this box?

BE ABLE TO ABLE TO is similar in meaning to CAN. The structure is as follows:

BE VERB + ABLE + TO + BASE VERBSome examples:

She is able to speak French.They are able to help us.He was able to escape before the guards saw him.He will be able to walk again in a few months.They may be able to help us.

We can use NOT or UN- for the negative form:She was unable to sleep.She was not able to sleep.

The question form:Was she able to sleep?

Usually, we use ABLE TO in place of can to show that something is a little difficult, or the outcome was in doubt. In this way, it means the same as MANAGED TO:

He managed to escape. (perform a difficult task)He was able to escape.

She was able to get the tickets. (outcome was in doubt)She managed to get the tickets.

COULD is the past tense of CAN

I could run faster when I was young. for polite requests:

Could you pass the salt?

is sometimes used with IF to describe an imaginary situation:If I was earning what my neighbour earns, I could retire by now.

is used to show uncertainty, in the same way that we use MIGHT:It could be true.It might be true

HAD BETTER to give warnings:

You had better be here on time tomorrow or youre fired.

to give strong piece of advice:You had better be careful. There are lots of snakes around here.

We often match HAD BETTER to OR ELSE:Youd better not tease the dog or else hell bite you.Youd better be careful, or else!

Learners often confuse HAD BETTER with SHOULD or MUST. HAD BETTER is used to give a warning, MUST for a situation where you have no choice and SHOULD is the standard phrase used to give advice:

Youd better not go out without a raincoat. (warning)You should try the cakes that Mary made. (advice)You must fill in this form to apply for leave. (no choice)

SHALL (is considered old-fashioned) for permission in a polite request:

Shall we dance?

MIGHT (and MAY or COULD) to show possibility:

The train might be late.

USED TO shows that something happened in the past, but no longer:

We used to live in Spain, but now we live in Italy. shows that the speaker is comfortable or familiar with something through habit

I am used to eating spicy food.In the first sentence, the meaning is a habitual action in the past. In the second sentence, the meaning is familiar with or comfortable with. Jack has dealt with tough clients many times so it is no problem for him.

*Note that the two meanings have different sentence structures.

Here, we are concerned with the second meaning, familiar with. The structure is as follows:BE VERB + USED + TO + GERUND

Jack is used to eating spicy food.Jill is used to working long hours.Ahmad is used to getting up early.

Past and future versions:George was used to doing physical exercise when he was a marine. George will be used to doing physical exercise after his year in the army.

We can also use the following form:BE VERB + USED + TO + NOUN/NOUN PHRASE

I am used to the rain.Mei Ling is used to tough customers.Chavez is used to people who talk in a British accent.

The negative and question forms:I am not used to spicy food.Are you used to spicy food?

STRUCTUREModal verbs are followed by the base verb:

Correct: We should go.Incorrect: We should going / We should gone

In the past tense, we add have:We should have gone

For the continuous form, add BE and the ING form:We should be going

For the passive forms, add BE (present) or BEEN (past) and the past participle:It should be eaten.It should have been eaten.

For most modals, the negative is formed in the following way:

MODAL + NOT + BASE VERB

may not gowill not seemust not dowould not have

In spoken English, we use the short forms, such as: wouldntcant

mustntwont

needntcouldnt

Tricky point: have to and must have the same meaning. However, mustnt and dont have to are different!

You mustnt drink alcohol after taking this medicine. (strong warning, it cannot be done)You dont have to take this medicine now. (recommendation; I can choose to take it or not)

PAST MODALS STRUCTUREModal verbs are: could, should, must, can, would, may, might etc. A common structure for modal verbs in the past is:

SUBJECT + MODAL + HAVE + PAST PARTICIPLE

Shemust have beendrunk.Youshould have toldme.Henrycould have died.Itmight have beenan accident.Iwould have spentless money.

*HAVE is always used in this structure, never HAS

Notes:

MUST has two meanings:1 compulsion: I must go.2 certainty: It must be expensive.

We use this structure only for meaning 2:It must have been expensive.

For meaning one, we use HAD TO:I had to go.

SHOULD: "We should have spent less money last vacation.

We use this structure to show regret for something that wedid not doin the past. (I spent too much money, I wish I had spent less.)

COULD has several meanings:1 past tense of can: I couldnt sleep.2 possibility: It could be a good idea.

We use this structure only for meaning 2:It could have been a good idea.

(meaning is the same asmight have,may have)

For meaning 1, we use COULDNT:I couldnt sleep.