剑桥语法在用中级27~28

27.1

2 e

3 b

4 f

5 a

6 d

27.2

2 could

3 can

4 could

5 can

6 can

7 could

8 can

9 could

10 could

27.3

2 could have come

3 could be

4 could have been

5 could have

6 could come

7 have moved

8 gone

27.4

3 couldn't wear

4 couldn't have managed

5 couldn't have been

6 couldn't afford (or couldn't manage)

7 couldn't have studied

8 couldn't stand

28.1

2 must

3 can't

4 must

5 must

6 can't

7 must

8 can't

9 must

10 can't

11 must

28.2

3 know

4 have left

5 be

6 have been

7 be looking

8 have heard

9 have been

10 be joking

11 get / be getting or have

28.3

3 It must have been very expensive.

4 They must have gone away.

5 I must have left it in the restaurant last night.

6 It can't have been easy for her.

7 He must have been waiting for somebody.

8 She can't have understood what I said. or She couldn't have understood what I said.

9 I must have forgotten to lock it.

10 They must have been having a party.

11 The driver can't have seen the red light. or The driver couldn't have seen …

12 He can't have worn them much