【判断题】If there are two goods, if a consumer prefers more of each good to less, and if she has a diminishing marginal rate of substitution, then her preferences are convex.
【简答题】He is waiting at the airline ticket counter when he first notices the young woman. She has glossy black hair pulled tightly into a knot at the back of her head—the man imagines it loosed and cascading...
【单选题】听力原文:M: I ran all the way to the bus stop, but the man at the ticket counter told me the bus left only 5 minutes ago. W: That's too bad. Those buses leave only every 50 minutes. Q: How long does the m...