为什么常用i find it interesting 而不常用i find it's interesting?

只有find+st+adj这种用法
附find用法：1. find +宾语+现在分词

She found a wallet lying on the ground.

她发现一只钱包在地上。

2. find +宾语+过去分词

He found the place much changed.

他发现这地方有了巨大的变化
3. find +（宾语）+形容词

She was found alone in the room.

发现她一个人在屋里。

4. find +宾语+副词

I”m so glad I found you in.

发现你在家我真高兴。
5. find +宾语+介词短语

They found him already in the care of a doctor.

他们发现已经有一位大夫在照顾他了。

6. find +宾语+名词

You will find it a difficult book.

你将发现这是一本难懂的书。

7. find +宾语+to be

This method was found to be practicable.

大家发现这方法很可行。

find作动词时,宾语不只能是名词性质的比如名词,代词,动名词或that引导的从句...it`s　interesting不能作为宾语,如果要作宾语,必须加一个引导词..I find that it`s interesting.(√)此时find是不及物动词,后面that不能省略...当然本句也可以这样表达:i find it interesting..此时,find 是及物动词,it是宾语,interesting是宾语补足语...

因为是从局