Ta có:used to+V-inf:đã từng làm gì trong QK,giờ không còn làm nữa.

Phủ định:didn't use to+V-inf

Nghi vấn:Did+S+use to+V-inf?

1.My mother used to work at a restaurant 3 years ago.

2.He used to be the president of Student Union.

3.There used to be many tree-line streets in my hometown.

4.My husband didn't use to do housework.

5.Children didn't use to play with high-tech devices at an early age.

6.The students didn't use to go to school by public transportation.

7.My city used to be a tourist destination.

8.Traffic jam didn't use to happen when I was small.