30.This machine,______for many years,is still working perfec
30.This machine,______for many years,is still working perfectly.
A.after which I have looked B.which I have looked after
C.that I have looked after D.I have looked after
为什么用B不用D?
我是想问 这里的which是否是做从句的宾语 这里为什么不能省略