高速缓冲存储器可以完全取代主存储器
A. 对
B. 错
We demanded that we __________ of any change in the plan.
A. informed
B. would be informed
C. be informed
D. had been informed
It’s necessary that he _________ a recognized qualification.
A. has
B. have
C. had
D. having
Much labour would have been saved if the electronic computers_________ before.
A. had invented
B. were invented
C. should have been invented
D. had been invented