Quotas or quantitative restrictions are the most common forms of non-tariff barriers. A quota limits the imports or exports of a commodity during a given period of time. The limits may be in quantity or value terms, and quotas may be on a country basis or global, without reference to countries. They may be imposed unilaterally and can also be negotiated on a so called voluntary basis.

货物保险是一种目的在于把风险从进口商和出口商的肩上转移到专门承担风险的保险人一方的活动。

选择权是指在特定的时间内按规定的价格购买或出售一种证券的权利。

在即期信用证情况下，提示汇票和正确无误的单据后便立即付款。

Quotas or quantitative restrictions are the most common forms of non-tariff barriers. A quota limits the imports or exports of a commodity during a given period of time. The limits may be in quantity or value terms, and quotas may be on a country basis or global, without reference to countries. They may be imposed unilaterally and can also be negotiated on a so called voluntary basis.

最著名的自由贸易区是北美自由贸易区，它是由美国、加拿大和墨西哥于1991年建立的。

许多人欢呼经济全球化带来的好处，但同时也有强烈的反对声音。

What are the advantages of the flexible exchange rate system?

In assessing the potential of a country as a market, people often look at per capita income. Similar to the case of national income and national product, per capita income and per capita GDP do not have much difference. So let's use per capita GDP to illustrate an economy's income level. It is calculated by dividing its total GDP by its population. Total GDP indicates the overall size of an economy, which is important in market assessment for durable equipment or bulk goods. Per capita GDP reveals the average income level of consumers, which is important when marketing consumer durables.

What is a counter-offer? What happens to the offer once a counter-offer is made?

Can you summarize the categories briefly under current counter trade?