只可用that.
下列情况只可用“that”而不可用“which”：
1.序数词或最高级形容词或叙述此修饰先行词,如first,best
2.先行词是all,little,much,few,anything,
nothing,something,none,the one时
3.先行词被any,few,little,all,no 修饰时
4.先行词被the only,the very,the same,
the last修饰时
5.先行词既有人又有物时.
6.当句中已有who时,为避免重复.
高中阶段知道这些就可以了.