It looked as if he had understood this question.的语法

问题描述:

It looked as if he had understood this question.的语法
为什么是It looked as if ,而不是It is looked as if

这里look是一个系动词.举个例子you looks beautiful today.翻译成“看起来...”记住系动词都不可以用被动语态,还有seem...smell..sound...都一样.