1. 我们五年前购买的那些二手汽车目前还在使用。（in use）
2. 在会议的过程中，许多著名的科学家作了有趣的发言。（course）
3. 我想在大学里主修管理。（management）
4. 去年在小山村里小住数日是我的一次激动人心的经历。（staying）
5. 这次考试比我原来想像的难得多。（much more）
6. 小李因为高烧病倒了。（be down with）
7. 老师不知道他为什么在练习中有这么多错误。（wonder）
8. 我们必须利用学校中优越的学习条件努力学习。（take advantage of）

十分感谢！！！

1、Those secondhand cars which we bought 5 years ago are also in use now。
2、In the course of the meeting，many famous scientists had made interesting speeches。
3、I want to major in management in the university。
4、The few-days-staying in the small moutain village was a fantastic experience。
5、The exam is much more difficult than I used to think。
6、Li was down with the high fever。
7、The teacher wondered that why there are so many mistakes in his exercises。
8、We must take advantage of the superior learning conditions in the school to study hard。

不客气！~~~