`1.` We were thinking about recycling. 

`2.` They were not singing at the concert.

`3.` I was not paying attention. (pay attention = chú ý)

`4.` Why weren't you  watching the movie?

`5.` Who was clapping at the end?

`***` CÔNG THỨC THÌ QUÁ KHỨ TIẾP DIỄN:

`+`  S + was/were + Ving.

`-`  S + was/were + not + Ving.

`?` Was/Were + S + Ving?

`@` Wh + was/were + S + Ving?

____________________

@onlychan._

`1)` 

`to` We were thinking about recycling

`-` Vì S là we ( số nhiều) `to` were

`2)`

`to` They were not singing at the concert

`-` They là số nhiều `to` were (not)

`3)`

`to` I was not paying attetion

`-` S là I `to` was ( not)

`4)`

`to` Why were you not watching the movie `?`

`5)` 

`to` Who was claping at the end `?`

`@` Cấu trúc QKTD

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

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

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