我觉得I found it is very interesting or I found it very interesting 两个自己都对，只不过两个句子结构不一样，第一个是I found that it is very interesting 定语从句， 第二个 interesting做宾语补足语。

Sorry - my Chinese is not great, but I don't think that 要去掉 sounds correct. Where did you see that?

found = simple past of "find" = 发现了 The actual meaning is "经过考虑后认为"

Oops! LOL 抱歉！ 我看了Gary 的回答然后没有完全明白你的意思。。。应该Dean的说明是对的。