mọi người ai giải giúp e mấy câu này với ạ giải thích rõ nữa ạ em đang cần ngay 16.What you (do) when I (ring) you last night? 17.Up to then I never (see) such a fat man. 18.I (not see) him since last Monday. 19.They had sold all the books when we (get) there. 20 I think he (leave) as soon as he (know) the news. 21.She (play) the piano when our guests (arrive) last night. 22.He (come) and (see) you soon. 23.I (come) as soon as I have finished my work. You (be) ready? 24.My mother (come) to stay with us next weekend. 25.Where you (spend) your holidays next summer? 26.Violets (bloom) in spring. 27.We (not live) in England for two years now. 28.I (never forget) what you (just tell) me. 29.They (prepare) the Christmas dinner at the moment. 30.When I last (stay) in Cairo, I (ride) to the Pyramids on a camel that my friend (borrow) the day before.