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