be afraid of 是某人害怕做某事 ； be afraid to 是因为某人/某事而害怕
be afraid of 害怕做某事be afaird to 不敢做某事 或 害怕做某事大致意思差不多
be afraid+句子be afraid of+某物（某结果）be afraid to do sth：表示不敢去做某事。
be afraid of 后接名词be afraid to 后接动词原形
