用作形式主语或形式宾语，而真正的主语或宾语在句末

Used in the position of the subject or object of a verb when the real subject or object is at the end of the sentence

你认为买新电视值不值?（形式宾语，代替动名词）

Do you think it worth buying anew TV?

我发现知道这一点很必要。注意：it在这里作形式宾语代替不定式

To know this point. e. g. : I found that it was necessary to know this point.

作者列举了某些使社会科学家难以进行实验的因素，而在同样的情况下，他的自然科学的同事们却可以进行实验。 （it为形式宾语代替真正宾语to conduct。

The author enumerate some of the factors which make it difficult for the sociologist to conduct experiments in the same way as his colleagues in the physical sciences.