smart是形容词作宾语补足语，也可以用不定式to be smart，当然，你在you之后加are也是对的，将you are smart看作是省略that的名词性从句，作consider的宾语。即：I consider you smart.= I consider you to be smart. = I consider (that) you are smart.又如：
They consider (that) the critical period is not over.他们认为危险期还没有过。（张道真《英语常用动词用法词典》）
We consider this (to be) very important. 我们认为这非常重要。《牛津高阶英汉双解词典》
We consider it (to be) true. = We consider that it is true.我们认为这是真实的。《现代英汉综合大词典》
