1.we cannot find the bike Tom lost last week.
2.He helped the boy you met in the park this morning.
3.The man that went to London last week will teach me English next year.
4.The book you gave me yesterday is an English book.
5.This is the bike I want to sell.
6.She is the girl who helped me last week.
这些都是考查定语从句的,注意引导词和时态就Ok.