Công thức thì QKĐ (V: to be)

(+) S + was/were + ... 

(-) S + was/were + not ... 

(?) Was/Were + S ... ? 

S số ít, I, he, she, it + was

S số nhiều, you, we ,they + were

Công thức thì QKĐ (V: thường)

(+) S + V2/ed 

(-) S + didn't + V1 

(?) Did + S+ V1?

DHNB: ago, last (year, month ...), yesterday, in + năm QK, ...

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7. ate 

8. Did you sit 

9. were 

10. missed

EX4:

1. Did 

2. didn't 

3. Was 

4. wasn't 

5. did 

6. Did 

7. weren't 

8. didn't 

9. didn't 

10. Was / wasn't