问题

Never before _____so highly successful in his attempts to change the weather slightly on a very small scale. [ ]

A: man has been
B: man is
C: will man be
D: has man been

正确答案是：

同类题型

Hi, Tom．Any idea where Mary is? ．一 She　______in the reading room．I saw her there just now．

The window _________ a beautiful view out over theriver.

the police thought he was the most likely one,since they had no exact proof about it,they had to set him free.

It has not been decided ____ they will leave

What about going out this evening? —Oh,I don’t know I’ve got a bit of headache,and,John’s coming to see me,so I ought to stay in[ ]