Here's a list of the modal verbs in English:

Modals are different from normal verbs:

1: They don't use an 's' for the third person singular.
2: They make questions by inversion ('she can go' becomes 'can she go?')
3: They are followed directly by the infinitive of another verb (without 'to')

Probability:

First, they can be used when we want to say how sure we are that something happened / is happening / will happen. We often call these 'modals of deduction' or 'speculation' or 'certainty' or 'probability'.

For example:

• It's snowing, so it must be very cold outside.
• I don't know where John is. He could have missed the train.
• This bill can't be right. £200 for two cups of coffee!

Ability

We use 'can' and 'could' to talk about a skill or ability.

For example:

• She can speak six languages.
• My grandfather could play golf very well
• I can't drive

Obligation and Advice

We can use verbs such as 'must' or 'should' to say when something is necessary or unnecessary, or to give advice.

For example:

• Children must do their homework.
• We have to wear a uniform at work.
• You should stop smoking.

Permission

We can use verbs such as 'can', 'could' and 'may' to ask for and give permission. We also use modal verbs to say something is not allowed.

For example:

• Could I leave early today, please?
• You may not use the car tonight.
• Can we swim in the lake?

Habits

We can use 'will' and 'would' to talk about habits or things we usually do, or did in the past.

For example:

• When I lived in Italy, we would often eat in the restaurant next to my flat.
• John will always be late!

For download this file click here

With most verbs the past tense is formed by adding -ed:

call >> called; like >> liked; want >> wanted; work >> worked

But there are a lot of irregular past tenses in English.(Look at next post)

Use

We use the past tense to talk about:

• something that happened once in the past:

I met my wife in 1983.
We went to Spain for our holidays.
They got home very late last night.

• something that happened again and again in the past:

When I was a boy I walked a mile to school every day.
We swam a lot while we were on holiday.
They always enjoyed visiting their friends.

• something that was true for some time in the past:

I lived abroad for ten years.
He enjoyed being a student.
She played a lot of tennis when she was younger.

• we often use phrases with ago with the past tense:

I met my wife a long time ago.

Questions and negatives

We use did to make questions with the past tense:

When did you meet your wife?
Where did you go for your holidays?
Did she play tennis when she was younger?
Did you live abroad?

But look at these questions:

Who discovered penicillin?
Who wrote Don Quixote?

For more on these questions see question forms

We use didn’t (did not) to make negatives with the past tense:

They didn’t go to Spain this year.
We didn’t get home until very late last night.
I didn’t see you yesterday.