`Answer:`

`1.` arrived - was sleeping

`2.` were crossing - shouted

`3.` went - were having

`4.` did - was coming

`5.` was having - stopped

`6.` was walking - saw

`7.` was writting - rang

`8.` was doing

`9.` was playing

`10.` went

`11.` did you do

`12.` was doing - was reading - was watching

`->`

`-` Cấu trúc thì Quá khứ đơn:

`(+)` S + Ved/V2

`(?)` Did +  S + V?

`-` Dùng để diễn tả một sự việc hay hành động đã diễn ra và kết thúc trong quá khứ.

`+` Thì Quá khứ tiếp diễn:

`(+)` S + was/were + V_ing

`-` Dùng để diễn tả một sự việc hay hành động đang xảy ra trong quá khứ ở thời điểm xác định