Underline the most suitable modal verb form in each sentence. 1 The average temperature on Earth can increase/may increase/must increase by as
much as 7°C by the end of the 21st century.
2 Governments cannot assume /could not assume /might not assume that the laws
they make will always be enforced.
3 The crisis must have been/should have been/could have been much worse, but
fortunately the authorities acted in time. .
4 Their slogan was 'Things should only get/can only get/must only get better'.
5 We're running out of time, I'm afraid. It can he/must he/should he nearly three
o'clock by now.
6 You won't have to wait for long. There should he/must he/may he another bus along
in about fifteen minutes, with any luck.
7 You could try looldng for the book in that secondhand shop. They might have/
must have/ought to have a copy, I suppose.
8 The burglars can't have got in/must have got in/might have got in through the
window. It's still locked.
9 Hello! You ought to he/must he/could be Diane Black. Pleased to meet you.
10 There's no point waiting here any longer. We could as well/should as well/might as
well go home.

Choose the answer (A, B or C) that best explains the meaning of each sentence.
1 They can't have realized what would happen in that case.
A Perhaps they didn't realize.
B We can be sure they didn't realize. J
C They were not allowed to realize.
2 There can't be two stations with exactly the same name!
A I suppose it's possible.
B I'm certain there are.
C I'm sure there aren't.
3 New technology might provide a solution to these problems.
A I'm sure it will.
B I suppose it's possible.
C It's important to do this.
4 You could have ended up in serious difficulties.
A You didn't do this.
B You did this.
C You wanted to do this.
5 Somebody must know the truth about this matter.
A It's important to do this.
B I suppose it's possible.
C I'm sure this is true.
Someone might have started the fire deliberately.
A I suppose it's possible.
B Luckily it didn't happen.
C We know this is true.