6. The Greens (be) _________to many countries in the world so far.
7. We (go) _____________________ to that village to do volunteer work several times.
8. Our teacher (explain) _____________________ to us how to use the printer already.
9. My pen isn’t here any more. Someone (take) _____________________ it already.
10. Mai (not finish) _____________________ her homework yet.
11. They (not see) _____________________ the film Titanic yet.
12. I (not see) _____________________ your brother yet.
III. Chia động từ ở 2 thì: Quá khứ đơn và Hiện tại hoàn thành (chú ý vào dấu hiệu).
1. Tom (call) __________________ his boss yesterday.
2. I (meet) __________________ Robert at the supermarket this morning.
3. We (fly) _____________ to Ha Noi several times, but last summer we (go)______ there by train.
4. When (your father/ give up) ___________________________ smoking?
5. My uncle (move) __________________ to Da Lat in 2005.
6. I (be) __________________ to Sa Pa twice since 2000.
7. We (spend) __________________ our summer vacation in Ha Long Bay last July.
8. I (watch) __________________ the film Titanic already.
9. The postman (deliver) __________________ the letter half an hour ago.
10. I (hear) __________________ the good news from Mary a few minutes ago.