sid/not clean/his room/at 8 p.m last night =>........... We/have/dinner/when tim arrived =>......... What/Jack/do/while/you/cook/dinner =>...........

Sid wasn't clean his room at 8.00p.m last night.

We were having dinner when tim arrived.

What was jack doing while you were cooking dinner.

Sid was not cleaning his room at 8.pm last night.

Sử dụng thì quá khứ tiếp diễn vì có dấu hiệu: 8 p.m last night là 1 mốc thời gian cụ thể trong quá khứ)

We were having dinner when Tim arrived.

Cấu trúc: S + was/were + V-ing when S + V-ed (Một hành động đang diễn ra thì 1 hành động khác xen vào)

What was Jack doing while you were cooking dinner?

S + was/were + V-ing + while + S + was/were + V-ing (2 hành động xảy ra đồng thời)