He looks much younger than he is.than后为什么会有主语和be动词

题目

He looks much younger than he is.than后为什么会有主语和be动词
He looks much younger than he is.如果这个句子是完整的,那he is后应是什么?都什么时候than后会有这种结构?

答案

He looks much younger than he is.
than后面是一个比较状语从句,he is 后面省略了for his age.
应翻译成：
他看上去要比他实际的年龄小许多.