17 ought to
18 must
19 should
20 ought not to
21 watches
22 go
23 doesn't study
24 doesn't study
25 teaches
26 starts
27 make/am trying
28 is happening
29 improves
30 am listening
31 spent
32 nam studied harder than I did last weekend
33 my father played golf yesterday
34 phong listened to music for two hours last night
35 she went to the supermarket yesterday
36 was taking/was using
37 was driving/was trying
38 had still waited
39 was always making
40 always complained
41 won't be
42 won't bring
43 won't tell
44 will you be
45 does he go
46 am going to move
47 is going to change
48 aren't going to buy
49 aren't going to tidy
50 are going to like