Ⅰ. afraid “害怕”是形容词,只能作表语,而不能作定语,后接of 短语或不定式,构成be afraid of sb. 和be afraid to do sth
① She is afraid of a snake. 她害怕蛇。
② The little girl is afraid to go out at night.
afraid +that clause “恐怕”,是婉转拒绝别人的一种表达方式。如:
① I’m afraid (that) I can’t go to the party. My brother is sick. 恐怕我不能去参加聚会了。我弟弟病了。
Ⅱ. fear “害怕”是动词,与be afraid 往往通用,但不如它常用(特别是在口语中)。如:
① We fear no difficulty.我们不怕困难。
② He feared to speak his mind.他不敢说出自己的想法。
③ Fearing that he would catch cold, I went out to see him.因为怕他会受凉,我走去看他。
Ⅲ. frightened adj “受惊吓的、害怕的”可做表语,也可作定语。如:
① She is too frightened to move.她太害怕了不能动弹。
② A frightened girl is crying. 一个受惊的女孩正在哭。