Mệnh đề quan hệ cĩ thể được rút gọn bằng cách dùng động từ nguyên mẫu cĩ TO hay hiện tại phân từ và quá khứ phân từ.
1/ Dùng To – Infinitive trong các cấu trúc câu sau:
a) S + V + Noun + Relative clause (Thường hai mệnh đề trong câu cĩ cùng một chủ từ) S + V + Noun + to – infinitive.
EX: We have a lot of work which we have to do today. We have a lot of work to do today. They need a garden which they can play in. They need a garden to play in. b)
(Thường hai mệnh đề trong câu khác chủ từ) EX: There are picture books which children can read. There are picture books for children to read.
Here is an application form that you have to fill in. Here is an application form for you to fill in. c)
EX: There are some letters which must be posted today. There are some letters to be posted today.
d)
EX: He was the last man who left the ship. He was the last man to leave the ship. Mary was the only girl who understand. Mary was the only girl to understand.
2/ Dùng hiện tại phân từ / quá khứ phân từ :
a) Hiện tại phân từ:
* Khi động từ trong mệnh đề quan hệ chỉ hành động đang xãy ra ở vào một thời điểm: EX: Do you know the girl who is talking to Tom? Do you know the girl talking to Tom? I was woken up by a bell that was ringing. I was woken up by a bell ringing. * Khi động từ trong mệnh đề quan hệ diễn tả một thĩi quen hay việc thường xuyên. EX: Boys who attended that school had to wear uniform.
Boys attending that school had to wear uniform.
b) Quá khứ phân từ khi động từ trong mệnh đề quan hệ ở dạng bị động: EX: The man who was injured in the accident was taken to hospital. The man injured in the accident was taken to hospital.
The money which was stolen in the robbery was never found. The money stolen in the robbery was never found.