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.
