1. is studying
-> thì HTTD diễn tả hành động đang xảy ra tại thời điểm nói
2. has been used
-> for + khoảng thời gian là dấu hiệu thì HTHT
3. In spite of taking a taxi, she arrived late for the meeting
-> in spite of N/Ving
4. He asked Marry how many boys there were in her class
-> S asked sb Wh- S V(lùi thì)
5. The last time she wrote to me was when we left school
-> The last time S V(QKĐ) was...
6. The last time I met him was in March
7. The test was so difficult that I can't complete it
8. If today weren't so cold, I wouldn't go swimming
-> Câu điều kiện loại II diễn tả hành động không có thật ở hiện tại / tương lai