`1.` The light had turned off before they got out of the office.

`-` CT: S + had + Vpp + before + S + Ved/c2

`=` S + Ved/c2 + after + S + had + Vpp

`->` Dùng thì QKHT vì câu đề cập đến một hành động xảy ra trước một hành động khác trong quá khứ

`-` turn off (phs v): tắt (đèn)

`-` get out (phs v): đi ra ngoài

`2.` By the time I began my work, she had quickly left.

`-` DHNB: by the time + S + Ved/c2 `->` Thì QKHT

`-` Form: S + had + Vpp

`-` V + adv `->` Bổ nghĩa cho động từ

`3.` After my father had finished his work, we came back home.

`-` CT: S + Ved/c2 + after + S + had + Vpp

`-` come back (phs v): trở về, trở lại

`4. ` Before my brother went to bed, he had read an interesting novel.

`-` go to bed: đi ngủ

`-` read a novel: đọc một cuốn tiểu thuyết

`5.` When Linh met her best friend in Bangkok, he had joined the Ever.

`-` Dùng thì HTHT ở vế sau vì hành động đã xảy ra trước một hành động khác trong quá khứ

`-` join sth: tham gia vào cái gì/tổ chức gì

`--------------`

`***` CT thì QKHT (Past Perfect):

`(+)` S + had + Vpp

`(-)` S + hadn't + Vpp

`(?)` (WH-/How-) + had + S + Vpp?

`->` Yes, S + had.

`->` No, S + hadn't.

`color{pink}{Vanie}`

`1`. The lights of the office had turned off before they got out.

`2`. By the time I began my work, she had quickly left.

`3` . After my father had finished his work, we came back home.

`4` . Before my brother went to bed, he had read an interesting novel. 

`5` . When Linh met her best friend in Bangkok, he had joined the Ever.

______________________________________________________________________

Công thức thì quá khứ đơn

(`+`) S + V-ed + ...

(`−`) S + didn't + V-inf

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

`***` Dấu hiệu nhận biết: Yesterday, ago, last,...

`+` Khoảng thời gian trong quá khứ

Thì quá khứ hoàn thành

(`+`) S + had + V-p 3

(`−`) S + had + not + V- 3

( `?` ) Had + S + V-p 3 ...?

`***` Dấu hiệu nhận biết: for, since, yet, already,...