11) The grass was yellow because it didn't rain all summer
12) The lights went off because we didn't pay the electricity bill
13) The children didn't do their homework, so they were in trouble
14) They didn't eat so we went to a reataurant
15) We couldn't go into the concert because we couldn't bring our tickets
16) She said that she hadn't visited the UK before
Do dài quá nên từ câu này mình chỉ ghi kết quả thôi nha ^^
17) haven't met
18) wasn't having
19) hasn't used
20) didn't study
21) went / had finished
22) had already seen
23) went
24) hadn't eaten
26) watched / had done
28) had gone / sitted / rested
29) had gone / went
30) won
31) told / had visited
34) watched / had done
35) had washed / slept
36) have stayed
Câu 25, 27, 32 và 33 mình không biết làm
Mong cậu chọn câu trả lời của mình!!! 

11) didn't rain
12) didn't pay
13) didn't do
14) didn't eat
15) couldn't bring
16) hadn't visited
17) haven't met
18) wasn't having
19) hasn't used
20) didn't study
21) went / had finished
22) had already seen
23) went
24) hadn't eaten
25) had already begun
26) watched/ had done
27) had he been/ was
28) had gone/ sat/ rested
29) had gone / went
30) won
31) told/ had visited
32) had/ prepared/ went
33) had/ watched/ rang
34) watched/ had done
35) had washed/ slept
36) have stayed