Grammar Reference

 

7.1 ■ have to and should

have to and don't have to

Affirmative and negative
I We You They	have to don't (= do not) have to			work.
He She It	has to doesn't (= does not) have to
Questions and short answers
Do	I we you they	have to	work?	Yes, I do. No, I don't.
Does	he she it			Yes, he does. No, he doesn't.

Use

• In affirmative sentences, we use have to to show that it is necessary to do something.
  We have to tidy our rooms on Saturday mornings.
  He has to wear black shoes at school.
• We use don’t have to when it isn’t necessary for someone to do something.
  You don’t have to pay for this course. It’s free.
  She doesn’t have to get up early at the weekend. She can stay in bed until 10.
• We use the question form Do I / you / we / they have to … ? or Does he / she / it have to … ? to ask if it is necessary to do something.
  Do we have to buy the tickets now?
  Does he have to take the test?

should and shouldn’t

Affirmative and negative
I You He / She / It We They	should shouldn't (= should not)		sit on this sofa.
Questions and short answers
Should	I you he / she / it we they	sit on this sofa?	Yes, you should. No, you shouldn't.

Form

• Should is used with an infinitive without to.
• The forms of should are the same for all persons.
• There is no auxiliary do in questions or negatives.

Use

• We use should to give advice, or when the speaker feels that it is important for someone to do something.
  You should always wear a helmet when you ride a bike.
  We should send an email to our cousin.
• We use shouldn’t to give advice, or when the speaker feels that it is important for someone not to do something.
  You shouldn’t worry so much!
  He shouldn’t shout at his little sister.

7.2 ■ Past simple: be and can

Past simple: be

Affirmative and negative
I He / She / It	was wasn't (= was not)		at home yesterday.
You We They	were weren't (= were not)
Questions and short answers
Was	I he / she / it	at home yesterday?	Yes, I was. No, he wasn't.
Were	you we they		Yes, you were. No, you weren't.

Form

• The past simple affirmative forms of be are was and were.
• The negative is formed by adding n’t (= not).
  You / We / They were in London last night.
  You / We / They weren’t in London last night.
  I / He / She / It was on the bus.
  I / He / She / It wasn’t on the bus.
• The past simple question form of be is formed by changing the order of the subject and the verb.
  Were you / we / they in London last night?
  Was I / he / she / it on the bus?

Use

We use the past simple form of be to talk about situations in the past.

Past simple: can

Affirmative and negative
I You He / She / It We They	could couldn't (= could not)		play the piano.
Questions and short answers
Could	I you he / she / it we they	speak English?	Yes, I could. No, we couldn't.

Form

• Could is used with an infinitive without to.
• The forms of could are the same for all persons.

Use

• We use could to describe ability in the past.