A、$30. B、$15. C、$10. D、$5. B生活交际类．事实细节题。女士说她以为帽子是半价出售，没想到还是10美元，男士回答说女士弄错了，买两件时第二件才半价。由此可知，买两顶帽子要花费15美元。

W: I didn’t expect the dormitory to be so noisy. There must be something we could do about it.
M: Maybe we could request the dormitory council to have it soundproofed.
Q: What does the man suggest doing?

W: I thought this hat was on sale for half price, but it still costs ten dollars.
M: You are mistaken. If you buy one, the second one will be half-priced.
Q: How much will two hats cost?