3.with whom--for whom
4.by which--in which
5.where--that/which或省略
6.it去掉
7.which--why
8.person helps--person who helps
9.which--when
10.why--that
3.with whom--for whom
4.by which--in which
5.where--that/which或省略
6.it去掉
7.which--why
8.person helps--person who helps
9.which--when
10.why--that