be afraid of be afraid on be afraid to be afraid at 的区别

e afraid of sth 害怕某物、某事 be afraid of doing sth .害怕会出现某种情况
be afraid on 不是固定搭配,介词on应该和后面的词相搭配的
be afraid to do sth.害怕做某事
be afraid at 因...而害怕