Bob! There's___Mr.Li waiting for you outside. But I don't know who he is.

问题描述:

Bob! There's___Mr.Li waiting for you outside. But I don't know who he is.
A、a B、an C、the D、/(讲解最好)

选A
翻译:Bob,外面有一个李先生在等你,但我不知道他是谁.
说话的人不知道是哪个人找Bob,只知道是一个姓李的先生,没有特指,所以选A