Thismachine,

問題詳情：

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

【回答】

B. which I have looked after 構成一個非限制*定語從句.

知識點：定語從句

題型：選擇題