Lý thuyết: Cấu trúc:

`-` When/while + S + V2/ed + O, S + was/were + Ving + O

hoặc S + was/were + when/while + S + V2/ed + O (có thể đảo thì):

Diễn tả một hành động đang xảy ra trong quá khứ (chia thì qktd) thì một hành động khác xen vào (chia thì qkđ)

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6, died

7, was raining

8, fell asleep

9, was sleeping

10, was chasing

11, was studying - came

12, was walking - met

13, woke - was washing

14, was working - phoned

15, were having - started

16, saw - were going

17, fell - was climbing

18, was walking - saw

19, burnt - was cooking

20, fell - was reading

`6.` died

`-` die `->` died `->` died

`7.` was raining

`8.` fell asleep

`-` fall `->` fell `->` fallen

`9.` was sleeping

`10.` was chasing

`11.` was studying `-` came

`->` come `-` came `-` come

`12.` was walking `-` met

`-` meet `->` met `->` met

`13.` woke `-` was washing

`-` wake `->` woke `->` woken

`14.` was working `-` phoned

`-` phone `->` phoned `->` phoned 

`15.` were having `-` started

`->` start `-` started `-` started

`16.` saw `-` were going

`-` see `->` saw `->` seen

`17.` fell `-` was climbing

`-` fall `->` fell `->` fallen

`18.` was walking `-` saw

`-` see `->` saw `->` seen

`19.` burnt`/`burned `-` was cooking

`-` burn `->` burnt`/`burned `->` burnt`/`burned

`20.` fell `-` was sleeping

`-` fall `->` fell `->` fallen

$\textit{*Diễn tả hành động đang xảy ra thì một hành động khác xen vào trong quá khứ}$

`+` Hành động đang xảy ra: QKTD: `\text{S + was/ were + Ving}`

    `*` I`/`She`/`He`/`It`/`Ngôi 3 số ít `+`was

    `*` You`/`We`/`They`/`Ngôi 3 số nhiều `+` were

    `*` While `+` QKTD

`+` Hành động khác xen vào: QKĐ: `\text{S + V2/ed}`

    `*` When `+` QKĐ

`***` Lưu ý: Trong 1 số trường hợp, When có thể đi với QKTD