Cấu trúc:
*Câu khẳng định: S + was/were + V-ing.
(was dùng cho danh từ số ít và were dùng cho danh từ số nhiều)
Eg: I was taking a bath before you arrived.
*Câu phủ định: S + was/were + not + V-ing
Eg: They weren't playing tennis at 7:00 yesterday.
*Câu nghi vấn:
A: Was / Were + S + V-ing?
B: -Yes, S + was/were.
-No, S + wasn’t/weren’t.
Eg:
T: What was you doing at 12 o'clock last night?
A: I was doing my homework.
