单选题
Man: Do you know Jason"s phone number?
Woman: ______
Man: OK. I might as well look it up in the phone book.
【正确答案】
B
【答案解析】[解析] “Not that I know of”是一个常用表达法，意思为“我想我不知道”。最符合本对话语境。“Just a second”意思为“稍等”；“I can"t think of it now”意思为“我现在想不起来”，意思勉强讲得通，没有B项常用。