=>

1. Not until I locked the room did I realize that I hadn't turned off the cooker. (đảo ngữ Not until + mệnh đề chỉ thời gian + TĐT + S V.)

2. Speeding is forbidden in this city. ( bị động is/am/are V3/ed)

3. Tim is the best chess player in the class. (Đề bài lỗi)

4. When did you take up badminton? (take up : bắt đầu một sở thích, môn thể thao)

$1$. Not until I locked the room did I realize that I hadn't turn off the cooker

$2$. Speeding in the city is forbidden by the law

⇒ Câu bị động

$3$. Sửa đề: No one else in the class is as good at chess as tim is (best)

⇒ Tim is the best person at chess in the class

4. When did you take up playing badminton?

⇒ take up: bắt đầu sở thích

@`text{HYen}`

#`text{Sếu}`