表示“害怕做某事”或“不敢做某事”,be afraid 之后可接不定式,也可接 of doing sth.如: She was afraid to tell [of telling] you.她害怕告诉你. She is afraid to go [of going] out alone late at night.她很怕深夜独自外出. 但若要表示担心可能会发生某事,则只能用 be afraid of doing而不能用 be afraid to do.如: She is afraid of lagging behind the others.她怕落在别人后面. She didn’t tell him because she was afraid of upsetting him.她没有告诉他,因为怕他不安.