dạng đúng của động từ trong ngoặc ở thì qua khứ tiếp diễn.
1. At this time last year, they ………were building... (build) ……… this house
2. I (drive) …was driving…… my car very fast when you called me.
3. I (chat) …was chatting…… with my friends while my teacher (teach) …taught…… the lesson yesterday .
4. My father (watch )…was watching…… TV when I got home.
5. At this time yesterday, I (prepare )……was preparing… for my son's birthday party.
6. What you (do) ……were you doing… at 8 pm yesterday?
7. Where you (go) …were you doing…… when I saw you last weekend
8. They (not go) …weren't going…… to school when I met them yesterday .
9. My mother (not do) ……wasn't doing… the housework when my father came home.
10. My sister (read) …was reading…… books while my brother (play) …was playing…… football yesterday afternoon.