Used to + V ( nguyên mẫu )

THÌ QUÁ KHỨ TIẾP DIỄN

KĐ : S + was/were + V-ing (+ O)

PĐ : S + was/were + not + V_ing (+ O)

NV : (Từ để hỏi) + was/were + S + V-ing (+ O)?

Dấu hiệu nhận biết : While , When , at the time , ...

used to+V nguyên thể$\neq$ be/get used to+V-ing

Dấu hiệu nhận biết thì qktd:

-at+giờ/this time+time in past(at this time yesterday/at 5'o clock yesterday afternoon..)

-when,as,while+qkđ

-while +qktd

Ex:When I came,she was crying.

      A dog crossed the road while I was driving.