be afraid, be afraid to do sth., be afraid of (doing) sth.
(1) be afraid 意为"担心,害怕",多用于口语,常用来表示一种歉意,或遗憾,后可接 so 或 not,也可接 that 从句。
I'm afraid (that) 其语意相当于 I'm sorry, but...。
-- Are we on time? 我们准时吗?
-- I'm afraid not. 恐怕不准时。
I'm afraid you'll get caught in the rain.
(2) be afraid to do sth 常表示"由于胆小而不敢做某事"。
She is afraid to be here alone.
He is afraid to jump into the river from the bridge.
(3) be afraid of (doing) sth. 常表示"担心或害怕某事(发生)"。
I was afraid of hurting her feelings.