I think it+adj+that+从句 是固定搭配
I think it's+adj...也是可以的,它是I think 后面加从句.
是这个句型：It's adj+to do sth/that+从句.跟find差不多.
e.g I find it difficult to learn English well.或者 I find it's difficult to learn English well.两句句子的意思是一样的.不过相比较而言,前者更好.
在理论考试中如果出现上述情况,选前者；
在实际应用当中,两者都可以……