Exercise 2:
1, haven't eaten CHÚC
2, have never been
3, yet BẠN
4, has worked
5, has worked HỌC
6, have found
7, not been TỐT
8, has given up
9, Have you read THI
10, haven't found
11, have lain HOẶC
12, have been
13, Have you ever tried KIỂM
14, have you taught
15, was TRA
Exercise 3:
1, for SẼ
2, since
3, for ĐẠT
4, for
5, since ĐIỂM
6, for
7, since CAO
8, for
9, since NHA
10, for