Unit 18: Modals | Grammar | B1
  • Hotline: 0901 384 171
  • Tel: (028) 35 173 345

Unit 18: Modals | Grammar | B1

Mustn’t is not the same as don’t/doesn’t have to. In the sentences “Customers must not park in front of the main gates.”
must not means it is forbidden.

However, in the sentences “You don’t have to go to the party if you don’t want to.”
don’t have to means it isn’t necessary.

Don’t/doesn’t have to can be replaced by needn’t :
E.G. You needn’t go to the party if you don’t want to.


Complete the gaps in the following sentences with: mustn't/don't have to /doesn't have to/needn't.

1. You _____________ play in the road. It's dangerous!

2. She _____________ treat Jimmy like a child. He's capable of looking after himself.

3. If Is just a joke. You _____________ get so angry.

4. I'd appreciate your help, but you _____________ do it if you don't want to.

5. Please tell your children they _____________ use bad language in the classroom.

6. Is it true that school pupils _____________ wear uniforms any more?

7. It's my brother's birthday on Saturday. I _____________ forget to buy him a present.

8. If you want to get promoted, you _____________ keep arriving late for work.

9. I'm going to be home late tonight. You _____________ wait up for me unless you want to.

10. You _____________ work so hard. The doctor ordered you to relax.

can/be able to

We use can or am/is/are able to to describe ability:
Some athletes can run/are able to run a long distance in a short time.
My mother can’t drive/isn’t able to drive.Could or was/were able to describes general ability in the past but was/were able to or managed to describes the successful completion of a specific action:
He was able to/managed to complete all the questions in the time given. (NOT could)

If such an action is not completed successfully, we can use couldn’t, wasn’t/weren’t able to or didn’t manage to:
We couldn’t/weren’t able to/didn’t manage to find the answers to the travel quiz.


Fill the gaps in the following sentences with can/can't/could/couldn't or the correct form of be able to/manage to:

1. I ___________ run fast when I was young but I ___________ now.

2. ___________ you get all the shopping done before the shops close?

3. My parents ___________ decide where to go on holiday so in the end they stayed at home.

4. We ___________ climb to the top of the mountain but we ___________ see the sea from where we were standing.

5. She ___________ speak French, even though she lives in France.

6. My son ___________ walk and talk by the time he was sixteen months old.

7. I'm afraid we ___________ get here earlier because of the traffic.

8. Fortunately, we ___________ catch the rabbits when they escaped from their hutch.

9. Johnny ___________ answer any of the questions in the Chemistry test.

10 .Some animals ___________ communicate by making sounds and gestures.