often的意思是经常时可以用单三,意思是频繁时就用原形,这是为什么?often的意思是经常时可以用单三，意思是频繁时就用原形（动词上加）

Question

often的意思是经常时可以用单三,意思是频繁时就用原形,这是为什么?
often的意思是经常时可以用单三，意思是频繁时就用原形（动词上加）

Answer 1

经常和频繁都是指频率
often就是一个频率副词,它不加单三,后面的动词加.比如:
She often does her homework at the classroom.
He often goes to swim.
It's often rains here in spring.