问题

I noticed that he was wearing shoes that did not match. He too hard to notice.

A:might be working
B:can have worked
C:must have been working
D:should have been worked

正确答案是：

同类题型

_ is the strength of union that all the difficulties,if any, can be dealt with

I won’t call you, ________ something unexpected happens.

Some businesses refuse products from the rainforests so as not to destroy them.

I’m afraid I have to give it up.—Don’t be discouraged. Remember __________sticks to his work will succeed one day.

They use computers to keep the traffic _________ smoothly.