`1`. was cleaned

`⇒` Theo ngữ cảnh nên ta dùng thì QKĐ bị động

`⇒` Cấu trúc: S + was/were + Vpp + by O

`2`. Lying

`⇒` Đầu câu thường là Ving hoặc To V

`3`. shouting - took - jumped - saving 

`⇒` Sau giới từ là Ving ( after , in )

`⇒` Hoạt động đang ở thì QKĐ

`⇒` Được nối với nhau bằng and

`4`. tried - have never used

`⇒` Dấu hiệu: once `→` thì QKĐ

`⇒` Dấu hiệu: never `→` thì HTHT

`5`. Writing

`⇒` Đầu câu thường là Ving hay To V

`6`. go

`⇒` Dấu hiệu: each July

`⇒` thì HTĐ.

1. The classroom is still very dirty. I don’t think it has been cleaned(1- clean).

2. (2-Lie)Lying on the beach on a sunny day is pleasant.

3. After (3-shout)shouting for help, she (4-take)took off her shoes and (5-jump)jumped in (6-save)saving him.

4. Once you (7-try)try Gloswhite toothpaste, you (8-never use)will never use anything else.

5. (9-Write)Had written the letter, she put it in an envelope.

6. Each July, George together with his family (10-go)goes to Spain for holiday.