7. Sorry,but you aren't allowed to smoke here
⇒ I'm afraid + S + V = Sorry, but + S +V
8. I think he can speak french very well.
⇒ to be able to + V(inf) = can + V(inf)
9. That's the girl whose brother is in prison.
⇒ Cấu trúc của whose: Whose + N + V + O
10. How long are you going to stay?
⇒ Câu trên với câu dưới nghĩa giống nhau.
--- XIN TRẢ LỜI HAY NHẤT NHA ^^ ---