1, D. has been ( DHNB thì HTHT: three times)

2, A. started ( DHNb thì quá khứ đơn : in 1939)

3, A. will go ( S + V TLĐ + as soon as/ when + S + V HTHT)

4, C. will have finished ( S + V TL + by the time + S + V HT )

5, A. has been ( DHNB thì HTHT: since + MTG)

6, B. is working ( DHNB thì HTTD: at the moment)

7, C. come ( V HT + until +V HT)

8, D. came ( DHNB thì QKĐ : yesterday )

9, C. have ever seen ( it is + the + first/ second... time; adj + est/ most adj + N + S + V HTHT)

10, C. will be watching ( DHNB thì TLTD: at 8 o'clock this evening)

11, A. phoned ( DHNB thì QKĐ: ago)

12, D. built ( DHNB thì QKĐ : three years ago)

13, C. is talking ( dựa ngữ cảnh : don't make noise)

14, B. has played ( S + V HTHT + since + S + V QKĐ)

15, D. have learnt ( DHNB thì HTHT : up to now)

16, D. has lived ( DHNB thì HTHT : for 15 years)

17, B. haven't eaten

18, B. had already slept ( when + S + V QKĐ, S + V QKHT)

19, D. had ( S + V QKHT + before + S + V QKĐ )

20, B. have you been ( DHNB thì HTHT: since )