问题如下：
In the Ricardian trade model, a country captures more of the gains from trade if:
选项：
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.
解释：
C is correct.
A country gains if trade increases the price of its exports relative to its imports as compared to its autarkic prices, i.e. the final terms of trade are more favorable than its autarkic prices. If the relative price of exports and imports remains the same after trade opens, then the country will consume the same basket of goods before and after trade opens, and it gains nothing from the ability to trade. In that case, its trade partner will capture all of the gains. Of course, the opposite is true if the roles are reversed. More generally, a country captures more of the gains from trade the more the final terms of trade differ from its autarkic prices.
考点：Ricardian mode
解析：
贸易条件指数=出口价格指数/进口价格指数X100%
A国 小麦 10元 牛仔裤100元
B国 小麦 20元 牛仔裤50元。
假设A国12元出口小麦到B国，进口80元价格牛仔裤。 贸易条件0.15
假设A国16元出口小麦到B国，进口50元价格牛仔裤。贸易条件0.32
显然第二中情况下，A国的收益更大。因为它出口的商品更贵，进口的商品更便宜。
好，那么我们再来算一下封闭状态下两国的牛仔裤与小麦的价格之比。A国是0.1,B国是0.4.
那是A国的贸易指数越接近0.4他的获利就越大。0.4代表什么？0.4就代表封闭状态下贸易对手国的两个商品的比价。
这也说明最好小麦以20元出口给B国，而牛仔裤以50元价格从B国进口。此时A国获得收益就是最大的。而此时的贸易条件就是0.4
如果A国以10元的价格，出口小麦，以100元的价格进口牛仔裤，那么他从贸易中获得收益就是0。此时的贸易条件就是0.15
所以这题C选项表达的就是这个观点。所以选C。就是本国的贸易条件要尽量和对手国封闭状态下商品价格之比接近才能获取利益。
B选项说反了，不入选.
A选项是一个打酱油的选项不用管它。因为贸易的每一个成员国都应该参与分工。
为什么答案里写的 如果A国以10元的价格，出口小麦，以100元的价格进口牛仔裤，那么他从贸易中获得收益就是0。此时的贸易条件就是0.15了？
