1) had forgotten

2) have already studied

3) spent

4) have bought

5) had learnt, went

6) spent, went

7) spoke

8) is washing

9) has your mother return

10) was doing

11) has drunk, gave

12) have you ever been

13) hasn't been reading

14) reached

15) I haven't recieved an answer to my letter yet

16) has finished

17) was training

18) bought

19) haven't been dancing

20) came, were playing

21) has your sister gone

22) has just recovered

23) have never been

24) were talking