一 、限制性定语从句和非限制性定语从句
[观察例句]
1．This is the place which is worth visiting.
2．Those who expect the worst are less likely to be disappointed.
3．His favorite hobbies are swimming and gardening，which have become a necessary part of his life.
4．My father was easily cheated，which surprised me.
5．The reason why he failed in the exam was that he didn't study hard.
6．We then moved to Paris，where we lived for six years.
