1.This is the pen that he bought yesterday.
2.He is the student who knows the answer to the question.
3. You could order food that you like.
4. The most exciting boy who is playing football is my brother.
5. The bookwhich you are most interested in is borrowed from Lucy.你确定所有的句子都是定语从句吗？回答这个问题后就采纳你确定