问题

It is not until recently ______ the scientists have found proof of there being water on Mars

A:when
B:that
C:how
D:what

正确答案是：

同类题型

The job will be offeredto is capable of performing it well.

With temperature ________ so rapidly,we could not go with the experiment. [ ]

________________________—-It’s warm.

下列句子划线词语解释不正确的一项是

23We went into a hall, on_____walls hung a few pictures of some famous scientists