`1)` arrived `-` was singing

`2)` was walking `-` met

`3)` called `-` was doing

`4)` wasn't running `-` hurt `-` was dancing

`5)` didn't see `-` walked

`@` Cấu trúc:

`-` Hành động đang xảy ra `to` QKTD

`-` Hành động xen vào `to` QKĐ

`-` QKTD: 

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

`( - )` S + Was/were not + V-ing

`( ? )` Was/were + S + V-ing `?`

`-` QKĐ

`( + )` S + Ved/ Cột `2`

`( - )` S + did not + V

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

`#Ph`

` 1`. arrived/was singing

` 2`. was walking/met

` 3`. called/was doing

` 4`. wasn't running/hurted/was dancing

` 5`. didn't see/was walking

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

` @` Một sự việc đang xảy ra (QKTD) , một sự việc khác xen vào ở quá khứ (QKĐ).

` @` Quá khứ đơn

` (+)` S + V-ed/V2 + ....

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

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

` @` Quá khứ tiếp diễn

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

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

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