经济学需求函数一阶导必须要会计算吗？不会解方程也听不懂怎么办？

老师，我在电脑端使用“提问”，要怎么才能把题目粘贴上来给你看呢？我的“问答”界面没有可以插入图片的地方

这个题是什么意思啊？从题目到答案都没懂

11 Which of the following trade restrictions is likely to result in the greatest wel- fare loss for the importing country? A A tariff B An import quota. C A voluntary export restraint. 自愿出口限制的welfare loss最大是因为原本给政府的税那部分也变成welfare loss了吗？为什么呢？

为什么根据HO model，一旦进行对外贸易，该国家哪个资源更丰富的受益更大?对于出口商品的需求更大了之后为什么gain变多？

7 In the Ricardian trade model, a country captures more of the gains from trade if: A it produces all products while its trade partner specializes in one good. B the terms of trade are closer to its autarkic prices than to its partner’s autarkic prices. C the terms of trade are closer to its partner’s autarkic prices than to its autarkic prices. 这一题为什么选C？在本国自给自足的价格和与其他国家进行贸易往来的价格有什么不一样？

李嘉图等价的结论是什么？

31 Themost likely argument against high national debt levels is that: A the debt is owed internally to fellow citizens. B they create disincentives for economic activity. C they may finance investment in physical and human capital 这一题B选项老师讲的和答案不一样，请分析一下B选项

27 The least likely explanation for why fiscal policy cannot stabilize aggregate demand completely is that: A private sector behavior changes over time. B policy changes are implemented very quickly. C fiscal policy focuses more on inflation than on unemployment 讲一下A选项吧？

21 Which of the following is a limitation on the ability of central banks to stimulate growth in periods of deflation A Ricardian equivalence. B The interaction of monetary and fiscal policy C The act that interest rates cannot fall significantly below zero 流动性陷阱和通货紧缩有什么关系吗？