$\text{*Structure: Past Perfect:}$

$\text{(+) S + had + Vpp + ...}$

$\text{(-) S + had not + Vpp + ...}$

$\text{(?) Had + S + Vpp + ...?}$

$\text{*Signals:}$

Until then, before, after, prior to that time, by the time, for, as soon as, by, ...When, when by, by the end of + thời gian trong quá khứ

`-` When, Before, After, By the time,....
$\text{*Usages:}$

`-` Diễn tả hành động xảy ra trước một hành động khác đã xảy ra trong quá khứ.

`-` Diễn rả hành động đã xảy ra và hoàn thành trước một thời điểm đã xảy ra trong quá khứ.

`-` Sử dụng trong câu đk loại `III`

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`11.` hadn't rained

`12.` arrived

`13.` hadn't bought

`14.` had rained

`15.` had eaten

`16.` met

`17.` sat

`18.` played

`19.` had snowed

`20.` had had

$chucbanhoctot$

$\textit{~KaitoKid!}$

11. didn't rain

12. arrived

13. hadn't bought

14. was raining

15. ate

16. met

17. sat

18. played

19. snowed

20. had had

*GT: - QKHT: (+) S + had + V3

                     (-) S + hadn't + V3

- QKTD: S + was/were + V-ing

- QKĐ: (+) S + V-ed/VII

            (-) S + didn't + V-infinitive.