题目内容：

It is careless of you make such a mistake,为什么用to,那意思是什么

优质解答

It is careless of you to make such a mistake.犯这样的错误,你太粗心了.
句型：It is 形容词 of sb to do sth,某人做某事是怎么样的.
这个句型中 it 是形式主语,to do sth 动词不定式是真正主语.