The quality of these recordings …………… not very good.
A. is
B. am
C. are
D. were
Chọn đáp án A
The effects of cigarette smoking …………. been proven to be extremely harmful.
Advertisements on TV ………… becoming more competitive than ever before.
Mr. John, accompanied by several members of the committee, ……….. proposed some changes in the rules.
The number of students who have withdrawn from class this quarter ……….. shocking.