gúp mình với ----- Nội dung dịch tự động từ ảnh ----- 15. My mother (feel) very nervous on the plane because she (not fly) before. (they/go) home when you (arrive)? 17. I (hear) the story before, so I (not find) it very interesting. she bought the most expensive one. 20. The children(be)very excited because they(not see)a tiger before. 21. Most people (leave) before the volcano (erupt). 22. By the time we (arrive) at the canyon, it (stop) snowing 23. They (spend) the night in the flooded area before help (arrive) 24. Simon (get) lost because he (not take) map with him. 25. I (find) my pen after I (buy) a new one.