they operated the new computer as if they ()skilled workers.
问题描述：
they operated the new computer as if they ()skilled workers.
这道题应该填had been?还是had been being?求讲解
答
had been
这是一题as if引导的虚拟语句,因为主句是过去式,所以从句要用过去完成时,也就是时态退一步那为什么不用being呢？had been being这个是过去完成进行时