Study these examples. The second sentence has a similar meaning to the first sentence

1 Perhaps Tom is tired.

may Tom may be tired.

2 I'm sure she isn't studying hard.

can't She can't be studying hard.

3 It is possible that they went out yesterday.

could They could have gone out yesterday.

4 It isn't necessary for Joe to come here.

have Joe doesn't have to come here.

5 You aren't allowed to use this car.

mustn't You mustn't use this car.

6 It wasn't necessary for him to book a table, but he did.

have He needn't have booked a table.

7 Let's meet again tomorrow night.

can We can meet again tomorrow night.

8 I advise you to call a doctor.

should You should call a doctor.

Complete each sentence with two to five words, including the word in bold.

1 It is possible that he has spent all the money.

could He... could have spent... all the money.

2 I advise you to take a course in literature.

should You … in literature.

3 It is possible that the police are questioning him.

may The police … him.

4 I'm sure he is lying about his age.

must He … about his age.

5 Let's have a break in five minutes.

can We … in five minutes.

6 It wasn't necessary for her to give me a lift, but she did.

have She … me a lift.

7 You aren't allowed to throw litter in the park.

mustn't You … litter in the park.

8 It isn't necessary for Mother to cook tonight.

have Mother … tonight.

9 It is possible that she has gone home.

could She … home.

10 Perhaps Dan is in hospital.

may Dan … hospital.

11 It wasn't necessary for her to call, but she did.

have She … but she did.

12 I advise you to have a rest.

should You … a rest.

Fill in the gaps with can, can't, could, couldn't or was/wasn't able to.

1 I had my hands full, so I... couldn't/wasn't able to... open the door.

2 When I was young, I … stand on my head.

3 Although he felt ill, he … finish all the paperwork.

4 Tony is clever. He … speak three languages.

5 I … afford that bag. It's too expensive.

6 Although it was dark, he … find his way through the woods.

7 I heard his voice calling me, but I … see him.

8 We're busy tonight, so we … come to the party.

9 When I entered the house, I … smell fresh bread baking.

10 I … drive a car. I learnt when I was eighteen.