bài 1
1 on. 2 on và since. 3 for. 4 at.5 since. 6 ago.7 at. 8 in. 9 on
bài2
1 have seen you since
2has not listened...since
3has eaten...for
4have lived...since
5have not studied
6 has not rained...since
7 have written...since
8have not had...since
9 has been...for
10 has not played...for