1 Yesterday I saw a really good film

2 I worked in this office in 1992

3 When does this lesson begin?

4 What was the matter? – I saw a road accident

5 Water boils at 100 degrees Celsius

It has been almost three years since she last visited her grandparents

If you do more research, you will improve your knowledge

6 mustn't => don't have to

7 would => could

8 can => must

9 can => can't

10 mustn't => didn't have to

1 leaves => will leave

2 will => would

3 couldn't => can

4 can => might

5 mustn't => must

15 A

16 B

17 C

18 C

19 A

20 B

6 by

7 never

8 am

9 since

10 decided

1 have

2 not

3 been

4 has

5 got

1 can't

2 must

3 can't

4 may

21 can

22 shouldn't

23 mustn't

24 can

25 used to

16 will

17 may

18 used to

19 will

20 must