(level 1) 请教大家两个关于international trade （Economics)中的问题

请教大家两个关于international trade （Economics)中的问题. 引号里面的话是 Kaplan notes里面的原话。相关内容也在课后题中有出现。

1.       关于Efforts of tariffs and quota， P218提到 “Quotas and tariffs in a large country could increase national welfare under a specific set of assumptions, primarily because for a country that imports a large amount of the good, setting a quota or tariff could reduce the world price for that good.”

请问大家， imposing quotas or tariffs by a large country 怎么可以reduce the world price从而还提高该国家的国家福利呢?

2.       关于the balance of payments (“BOP”) accounts including their components部门，在P220有提到 Current account comprises three sub-accounts including unilateral transfer. Kaplan notes还说 “Unilateral transfers are one-way transfers of assets, such as money received from those working abroad and direct foreign aid. In the case of foreign aid and gifts, the capital account of the donor nation is debited.”

书中关于unilateral transfers既提到了current account又提到了capital account. 那么 unilateral transfers (in the case of foreign aid and gifts) 究竟是与 current account, or capital account, or both相关呢?

多谢啦～～～