which是什么意思,which怎么读

who / whom(宾语) 指代物 which 既指人又指物 that "谁的,什么的"
不定式代替一个定语从句she had little time left in which to make
b: which girl(哪个女孩)?
which sentence describes one's mother tongue or a
时whom/which不能省略,也不能用that替换.