来自郭萍的问题
havedifficulties(in)doing和havedifficulty(in)doing有什么区别?
havedifficulties(in)doing和havedifficulty(in)doing有什么区别?


havedifficulties(in)doing和havedifficulty(in)doing有什么区别?
havedifficulties(in)doing和havedifficulty(in)doing有什么区别?
没有前一种写法,difficulty是形容词,怎么会有单复数?