1 . be afraid of sth 害怕某事。如：
Are you afraid of dogs? 你害狗吗?
There’s nothing to be afraid of. 没什么可害怕的。
比较：
He is afraid of her. 他怕她。
He is afraid with her. 跟她在一起时，他很害怕。
2 . be afraid of doing sth
担心会发生某事或某情况。如：
She was afraid of waking her husband. 她怕吵醒她丈夫。
I was afraid of hurting her feelings. 我怕伤害她的感情。
注：be afraid of doing sth 表示担心会发生某事或某情况时，其后也可用 be afraid that 替换。如：
He was afraid of losing face. =He was afraid he’d lose face. 他怕失面子。
害怕做某事或不敢做某事。如：
I’m afraid of telling her. 我不敢告诉她。
He was afraid of jumping. 他不敢跳。
3 . be afraid to do sth 害怕做某事或不敢做某事。如：
He was afraid to fly in a plane. 他不敢坐飞机。
He was afraid to go into the house and meet his father. 他不敢进屋去见他父亲。
注：以上两类句型的异同之处：表示担心会发生某事或某情况，只能用 be afraid of doing sth, 而表示害怕做某事或不敢做某事等，则两者都可用。如：
Don’t be afraid to ask [of asking] question. 不要害怕问问题。
He is afraid to go out [of going out] alone at night. 他不敢晚上一个人出去。
