`12.` Didn't go

`->` Last year là DHNB của QKT : S + didn't + V + O

`13.` Saw

`->` Last night là DHNB của QKĐ : S + Ved + O

`14.` Was watching

`->` At seven o'clock last night là DHNB của QKTD : S + were/was + Ving

`15.` Didn't meet

`->` Last week là DHNB của QKĐ : S + Ved + O

`16.` Helped

`->` Yesterday là DHNB của QKĐ : S + Ved + O

`17.` Did she lose

`->` Last Sunday là DHNB của QKĐ : Did + S + V?

`18.` Was she doing

`->` At this time yesterday là DHNB của QKTD : S + were/was + Ving

` 12. ` didn't go

` - ` DHNB: Last year ` => ` chia thì QKD

` - ` ` ( - ) ` S + did + not + V - inf

` 13. ` saw

` - ` DHNB: Last night ` => ` chia thì QKD

` - ` ` ( + ) ` S + V ( 2 / ed )

` 14. ` was watching

` - ` DHNB: At seven o'clock last night ` => ` thời gian cụ thể ` => ` chia thì QKTD

` - ` ` ( + ) ` S + was / were + V - ing

` 15. ` didn't meet

` - ` DHNB: Last year ` => ` chia thì QKD

` - ` ` ( - ) ` S + did + not + V - inf

` 16. ` helped

` - ` DHNB: Yesterday ` => ` chia thì QKD

` - ` ` ( + ) ` S + V ( 2 / ed )

` 17. ` Did she lose

` - ` DHNB: Last Sunday ` => ` chia thì QKD

` - ` ` ( ? ) ` Did + S + V - inf?

` 18. ` was she doing

` - ` Diễn tả ` 1 ` hành động đang diễn ra mà ` 1 ` hành động khác chen vào ` => ` dùng thì QKTD

` - ` ` ( ? ) ` Wh_q + S + was / were + ( not ) + V - ing?