Some of these expressions are commonly used for many years

问题描述:

Some of these expressions are commonly used for many years
commonly 为什么不用common呢?前面不是are吗?这里不是应该用形容词吗?

因为这里的commonly是修饰后面的use的,这里是副词修饰动词
be used for 固定搭配,.是用来.的