(1) 在非正式英语中，be afraid (of)要比fear更常见。

• Don't be afraid , child.
  不要怕，孩子。
• Are you afraid of the darkness?
  你害怕黑暗吗？

(2) I'm afraid 往往指“很抱歉，对不起，恐怕是……”，用于抱歉性的拒绝或透露坏消息等。

• I'm afraid I can't help you.
  我怕不能帮助你。
• I'm afraid your wife's had an accident.
  恐怕是你的妻子出了事故。

(3) I'm afraid not 和I'm afraid so常用于答话中。

• A: Can you lend me 10 pounds?
  你能借给我10英镑吗？
  B: I'm afraid not.
  我怕是不能。
• A: It's going to rain.
  要下雨了。
  B: Yes, I'm afraid so .
  是，怕是要下了。

(4) 通常在afraid前不用very，但可用very much，特别是在I'm afraid作“很抱歉，对不起(I'm sorry)”解时。

• I'm very much afraid he's out.
  很抱歉，他外出了。

(5) ①be afraid of doing, be afraid to do两个短语有时差别不大。

• I'm afraid to tell her/of telling her about it.
  这件事我不敢告诉她。

②但当说及意外发生或不想或无法选择的事情时，只能用of doing的形式。

• I'm afraid of falling into the swimming pool.
  我害怕掉进游泳池里。
• She was afraid of waking her husband (She didn't want to wake him).
  她担心吵醒了她丈夫。

③用不定式时有时意为“担心，不敢”。

• She was afraid to wake her husband (She feared that he might be angry with her).
  她不敢弄醒她丈夫。
• She was afraid to be seen speaking to him.
  她担心跟他讲话会被人看见。
• Don't be afraid to ask for my help.
  不要害怕向我求助(尽管向我求助)。