1. We have not seen him since Christmas Day.
Hiện tại hoàn thành : S + have/has + Past Participle
2. The novel was so interesting that I stayed up all night to read it.
Cấu trúc so...that : S + be + so + adj + that + S + V
3. My elder brother studies hard this year in order to pass the entrance exam to the university.
Cụm in order to + INF
4. The thief suddenly realized that he was being watched by the police.
Câu bị động thì quá khứ tiếp diễn: S2 + was/ were/ being + Past Participle + by + S1