【正确答案】 C

【答案解析】[听力原文]
M: How much are the carnations and the roses?
W: One dollar for each carnation and one and a half for each red rose.
M: Then I'd like a dozen red carnations and half a dozen red roses.
W: I bet it's for your mother, as it's Mother's Day today.
M: Well, not completely true. It happens to be her birthday.
W: Oh, really? I guess she must be very happy to receive these beautiful carnations from you.
M: Yeah, she will. She really likes flowers. So I buy her some every year. I'd just wish they would stay fresh longer than they do.
W: Put a little sugar and vitamin C in the water. They'll stay flesh for days.
M: Really? I'll tell my mother. And thanks for your suggestion.
W: That's all fight. Happy birthday to your mother!

What day is it today?

[解析] 此题属于事实细节题。题目询问今天是什么日子。由对话内容“as it's Mother's Day today”(因为今天是母亲节)和“It happens to be her birthday.”(今天碰巧是母亲的生日。)可知正确答案是选项C(母亲节，同时又是男士妈妈的生日)。
选项A和选项B都不够全面，故不选。 选项D的后半部分有误，不是女士的生日。

【正确答案】 D

【答案解析】[听力原文]
How much does the man spend on red roses?

[解析] 题目询问男士买玫瑰花费多少钱。由女士的话可知玫瑰花的价格是“…a half for each red rose”，男士说“I'd like...half a dozen red roses.”因此正确答案应该是选项D(9美元)。
此题需听清花的价格和需要的数量，以及问的花的品种，这样就不会误选A项、B项和C项。选项B(12美元)是买康乃馨花费的数额。选项D(21美元)是男士所需要付的总的金额数。

【正确答案】 B

【答案解析】[听力原文]
What does the woman suggest the man put in the water?

[解析] 题目询问女士建议男士往水里放什么。由对话的相关内容“Put a little sugar and vitamin C in the water.”可知应放糖和维生素C，因此选项B为正确答案。
解答此题需要听清、听全女士的建议。而选项A(糖)和选项C(维生素C)都不够全面。选项D在文中未提及。