核心问题
“Could I speak to Ann, please?” “I'm afraid not.”
I'm afraid not 是什么意思？其中的 not 是否定哪个成分的？
词典解答
not 如同 so 一样, 可以代替整个 (that) 从句 [参见 guess(I guess not)] :
A: Has the news reached home yet? (消息已送到家了吗?)
B: I'm afraid so. (我想已送到家了。)
B: I'm afraid not. (恐怕还没有送到家。)
上句中的 not = (that) the news has not reached home。不难看出，你所提问的句子中的 not 代替的是 (that) you can't (couldn't) speak to Ann。下面是类似的例句：
“Have you got a work permit?”——“I’m afraid not.” “你有工作许可证吗?”——“对不起，我没有。”
[句意]对不起,你不能跟安讲话。
练习题
请做下面的英语试题：
"Do you think he will pass the entrance examination?" "____."
A. I'm afraid not B. I'm not afraid C. I'm not afraid of that D. I'm not afraid he will not