`1.` was playing `-` entered

`2.` was studying `-` came

`3.` was washing `-` rang

`4.` was eating `-` were drinking

`5.` was watching `-` jumped

`6.` didn’t hear `-` was sleeping

`7.` was `-` went `-` was shining `-` was singing

`8.` were talking `-` walked

`9.` went `-` weren't `-` were playing

`10.` fell `-` was reading

`11.` enjoyed `-` was snowing `-` was shining

`12.` was snowing `-` left

`13.` were sitting `-` started

`14.` was talking `-` was seeing `-` finished `-` listened

`15.` were climbing `-`saw

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

`@` Cấu trúc của những câu trên:

`-` Cấu trúc: When `+` S `+` V(QKĐ), S `+` V(QKTD)

`->` Diễn tả hành động xảy ra cắt ngang một hành động khác trong quá khứ.

`-` Cấu trúc: When `+` S `+` V(QKTD), S `+` V(QKĐ)

`->` Diễn tả một hành động đang diễn ra thì hành động khác xen vào.

`-` Cấu trúc: When `+` S `+` V(QKĐ), S `+` V(QKĐ)

`->` Diễn tả hai hành động xảy ra song song hoặc liên tiếp trong quá khứ.

`-` Cấu trúc: While `+` S `+` V(QKTD), S `+` V(QKTD)

`->` Diễn tả hai hành động xảy ra đồng thời, song song trong quá khứ.

`-` Cấu trúc: While `+` S `+` V(QKTD), S `+` V(QKĐ)

`->` Diễn tả hành động đang diễn ra thì một hành động khác xen vào. Hành động làm gián đoạn chia thì quá khứ đơn.

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

`-` Cấu trúc thì QKĐ:

`+` Đối với động từ tobe:

`(+) S + was//were + N//Adj`

`-` Trong đó:

`+` I/ He/ She/ It / Danh từ số ít / Danh từ không đếm được `+` `was`

`+` We/ You/ They/ Danh từ số nhiều `+` `were`

`(-) S + was//were + n o t + N//Adj`

`(?) Was//Were+ S + N//Adj + ...?`

`+` Đối với động từ thường:

`(+)` S `+` Ved/C`2` `+` O

`(-)` S `+` didn't `+` V-inf `+` O

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

`-` Dấu hiệu nhận biết:

`->` Yesterday: Hôm qua.

`+` Last `+` N `:` Last night/ last week/ last month/ last year ...: Tối qua/ tuần trước/ tháng trước/ năm ngoái ...

`+` Ago: cách đây (two hours ago, two weeks ago …)

`-` Cấu trúc thì QKTD:

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

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

`(?)` Was/Were `+` S `+` V-ing `+` ...`?`

`-` Dấu hiệu nhận biết:

`->` At `+` giờ `+` thời gian trong quá khứ.

`->` At this time `+` thời gian trong quá khứ. 

`->`  In the past `:` Trong quá khứ ...

`->` In `+` năm ... `:` Vào năm ...

1. Peter was playing a video game when his brother, Jack, entered the room.

2. I was studying for my English test when my mother came home from work.

3. Emma was washing the dishes when the telephone rang.

4. I was eating a sandwich while my parents  were drinking coffee.

5. I was watching a DVD when my cat jumped on me.

6. I didn’t hear the thunder during the storm last night because I was sleeping

7. It was beautiful yesterday when we went for a walk in the park. The sun was shining. The birds was singing.

8. My brother and sister were talking anout something when I walked into the room.

9. Tom went to his friend’s house, but the boys weren’t there. They were playing soccer in the vacant lot down the street.

10. The little boy fell asleep while his mother was reading him a story.

11. I really enjoyed my holiday last January. While it was snowing in Iowa, the sun was shining in Floria.

12. It was snowing when I left home this morning.

13. It was a sunny afternoon and people were sitting on the grass in the park. Then suddenly it started to rain.

14. My brother was talking on the phone when I arrived, but when he was seeing me, he finished the call. Perhaps he thought that I listened to his conversation.

15. We were climbing the wall when the gardener saw us.

Giải thích:

S1 + Ved/V2 +.... + when/ because + S2 + was/were + Ving + ....

=> Diễn tả một hành động xảy ra trước một hành động khác trong quá khứ

S1 + was/were + Ving + ... + whi;e/but + S2 + was/were +Ving +....

=> Diễn tả một hành động đang xảy ra thì bị một hành động khác cắt ngang

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