Shehadthreesons,all___becamedoctors.
a.ofwhich
b.which
c.ofwhom
d.who
请问这题是考什么知识点的?要选择哪一项?请说明原因,谢谢!
那主语是she谓语是had宾语是?all___becamedoctors在句中是充当宾语吗?