Ответ:

1.

1) b

2) a

3) c

4) c

5) b

6) a

7) b

8) a

9) c

10) a

2.

1) should

2)must

3) could

4)may

5)can

6)have

7)had

8) mustn't

3.

1) - the pupils aren't writing a dictation

? Are the pupils writing a dictation

2) - the pupils haven't written a dictation

? Have the pupils written a dictation

3) - the pupils don't usually write a dictation

? Do the pupils usually write a dictation