1. The last time we saw him was on Christmas Day. (seen)

We __have not seen her since______________________________________ Christmas Day.

* SD cấu trúc HTHT: S + have/has + V(pp) + since + mốc thời gian.

2. It was such an interesting novel that I stayed up all night to read it. (so) 

The novel was _interesting so_____________________________ I stayed up all night to read it.

* dịch: quyển tiểu thuyết thật thú vị nên tôi đã thức cả đêm để đọc nó

3. My elder brother studies hard this year so that he can pass the entrance exam to the university. (order)

My elder brother studies hard this year __in order to_________________ the entrance exam to the university.

* in order to: mệnh đề phụ chỉ mục đích

dịch: Anh trai tôi năm nay học hành chăm chỉ để thi đậu vào trường đại học

4. The thief suddenly realised that the police were watching him. (being)

The thief suddenly realised that he __was being watched__________________________ by the police.

* dùng dạng bị động của thì QKTD: S + was/were + being + Vpp + (by O)