(B) It+被动语态+that从句

It is admitted that…应当承认

It is believed that…据信，人们认为 

It is claimed that…有人主张，据称 

It is emphasized that…要着重指出 

It has been proved that…巳经证明 

It can be seen that…可见，不难看出 

It was noted above that…前巳指出

(C) It is+名词十that从句

It is the case that…情况是这样的 

It is a pity that…可惜，遗憾的是 

It is no secret that…不用讳言，诚然

It is no wonder that…难怪，......并不奇怪

It is worth notice that…值得注意的是

(D) It+不及物动词+that从句 

It appears that…看来，似乎

It follows that…由此可见，因此 

It happened that...幸好，碰巧 

It seems that…好象，看起来

It turns out that…结果是，从而 

(E) It+其它结构+ that从句

It has been made clear that…已经查明

It makes little sense that.....(是）没有意义（的)

It seems possible that…看来（是）可能(的）

It used to be said that…过去人们常说 

在以上5类句型中，尤以前两种句型最为多见。

（二）作形式宾语

当英语的动同不定式短语、动名词短语或从句充当句中谓语动词的宾语，而句中又有宾语补足语时，出于句子结构的需要，常将这些宾语置于补足语之后，而将代词it放在原宾语的位置上，此时的it即为形式宾语。由于it在这种情况下无词汇意义，所以翻译时应减去不译。

A. 代替动词不定式

8) The guided projectile enables it possible to achieve the first hit.

制导炮弹使首发命中成为可能。