=>
31. Nam offered to clean the windows for Mai.
-> offer to V : đề nghị
32. Meat isn't as expensive as fish in some areas of the country, is it?
-> so sánh bằng as adj as
-> vế giới thiệu phủ định -> câu hỏi đuôi khẳng định
33. The last time Hoa was seen was on her birthday.
-> the last time S V2/ed (lần cuối)
-> bị động QKĐ was/were V3/ed
34. The boys would rather play soccer than stay indoors.
-> would rather V than V : thích làm gì hơn
35. Nam doesn't like chocolate cakes and his parents don't, either.
-> either (đồng tình câu phủ định)
36. That old house has just been sold.
-> bị động HTHT have/has been V3/ed
37. The cake was so hard that I couldn't eat it.
-> so adj that : quá...đến nỗi
38. It took two hours to fly from Ha Noi to Ho Chi Minh city.
-> take time to V ~ spend time Ving
39. John advised Mary not to lend that man any more money.
-> advise sb (not) to V : khuyên ai (không) làm gì
40. How long have you learnt English?
-> how long + HTHT : bao lâu?