we are ___students.

问题描述:

we are ___students.
1.thirteen years old 2.thirteen-year-old
选哪一个,
主要是第一个为什么不对?

2.第一个只能做表语,即只能跟在BE动词之后,不可以做定语修饰名词,所以we are thirteen-year-old students.=We are thirteen years old .第二个则可以做定语修饰名词,后面可以跟名词.