Question

Do you think it ____to learn English. A、helpful B、helps C、helping

答案是A。It is helpful to do .但是在这里为什么可以省略掉is呢？

Answer 1

因为think＋it（形式宾语）+形容词或名词（宾补）+不定式／动名词／从句（直接宾语）

更多例句
I don't think it possible to master a foreign language without much memorywork．

我认为没有大量的记忆劳动要掌握一门外语是不可能的。

I think it best that you（should）stay here．我想你最好呆在这里。

I think it no use writing to him．我认为给他写信没用。

Answer 2

think find 这样的词 后面可以直接加形容词
I find it hard to learn Russian.比如这样