麻烦大家`帮我出一份关于定语从句的试卷..

1. Don’t talk about such things of __________ you are not sure.
A. which B. what C. as D. those
2. Is this the factory __________ you visited the other day?
A. that B. where C. in which D. the one
3. Is this factory __________ some foreign friends visited last Friday?
A. that B. where C. which D. the one
4. Is this the factory __________ he worked ten years ago?
A. that B. where C. which D. the one
5. The wolves hid themselves in the places __________ couldn’t be found.
A. that B. where C. in which D. in that
6. The freezing point is the temperature __________ water changes into ice.
A. at which B. on that C. in which D. of what
7. This book will show you __________ can be used in other contexts..
A. how you have observed B. what you have observed
C. that you have observed