Question

这道选择题选哪个啊，为什么呢？

It _______ thest rare books that have benn stolen from the library.
A was B were C are D is
It _______ these rare books that have been stolen from the library.
A was B were C are D is
句子也打错了，不好意思

Answer 1

选D。
这道题考察的是强调句式：It is/ was + 被强调部分+ that + 其他
强调句式要注意的有以下几点：
1. 形式上，It is/ was ……that ……中，is/ was 只有这两种时态，由本句话的时态来决定是用is还是was，不存在are或were的形式；
2. 当被强调部分是主语并且是人时，that可以换成who
e.g. It was Tom who/ that picked up a book on the playground.
3. 主谓一致方面：如果被强调部分是主语，谓语由该主语决定，不受其他影响
e.g. It is I who am to blame for the matter.
这道题考察的是第一个知识点。

Answer 2

is 这句子是考察强调句形 it is/was +强调部分+that+句子. 因句子中用的是现在完成时所以要用is

Answer 3

D, It is that...句型，be动词的时态由that后面的时态决定。