为什么这里不能用should do it?
问题描述：
为什么这里不能用should do it?
3.Directions:Each of the following sentences has four underlined parts marked a,b,c and d.Identify the one that is not correct.Then,mark your answer by blackening the letter of your choice on the Answer Sheet.
On the whole this composition is well done,but you should do it in black ink instead of red.
(A) this composition
(B) should do it
(C) in
(D) instead of
该选的答案为B,为什么?如果这里不能用should do it,那么该用什么呢?
答
should have done it