用介词+which/whom 完成下列句子

用介词+which/whom 完成下列句子
There used to be a time _____ the Chinese people struggled for freedom.
He lives in an old room, the roof_____has been damaged in the storm.
In our class all the fifty students,only one ______didn't pass the exam,took part in the final exam.
The way _____one student studies might be quite different form that of another student.
Can you see the desk______ there is a book and two pens?
The man ______I share the room is a young teacher fresh from college.
He works in a factory, at the back____there is a river.