`1.` Mary is not old enough to see this film.

`-` S + Be/V + adj/ adv + enough + (for someone) + to do something : Đủ... cho ai đó làm gì...

`2.` If I hadn't been very busy, I could have gone to the meeting.

`-` Câu điều kiện loại `3` : If S + had P2 , S + would/could/might + have P2

`3.` I'm going to have my TV set repaired tomorrow.

`-` Have sth done: có thứ gì được làm bởi ai  

`4.` She asked John to repeat what she had said.

`-` Cầu khiến : S + asked/ told/ demanded,… + O + (not) + to V 

`-` QKĐ `->` QKHT

`5.` The date of the meeting will be had to change.

`-` Bị động TLĐ:  S + will be + V3/P2 by O

Đáp án:

$1.$ Mary is not old enough to see this film.

`-` S + be / V (not) + adj / adv + enough + to do sth

$2.$ If I hadn't been very busy, I could have gone to the meeting.

`-` Câu điều kiện loại III `:`

`->` If + S + had + V3 / PII, S + could / would / might + have + V3 / PII

$3.$  I'm going to have my TV set repaired tomorrow.

`-` Bị động nhờ vả `:` S + have / get + sth + V3 / PII ( by O ).

$4.$ She asked John to repeat what she had said.

`-` Câu tường thuật dạng cầu khiến `:`

`->` S + asked O + to V

`-` Lùi thì: Quá khứ đơn `->` Quá khứ hoàn thành 

$5.$ The date of the meeting will be had to change.

`-` Bị động Tương lai gần $(+)$ S + will + be + V3 / PII ( by O ).

`-` Chia động từ: have - had - had