a. Where is the teacher going to spend his summer vacation?

−- Cấu trúc nghi vấn thì TLG: (Wh_) + be + S + going to + V1?

b. Ho Chi Minh has a larger population than Hue does

−- Cấu trúc SSH trạng từ ngắn: S1 + V + adv + ER + than + S2

c I think we should go to the museum by taxi because it is too far

−- should + V1 : Nên