Quotas or quantitative restrictions are the most common forms of

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.
【正确答案】：配额或数量限制是非关税壁垒最常见的一种形式配额在一定时期内限制一种商品的进出口。其限制可以以数量计算也可以以价值计算,配额可以是针对国家的或者是全球性的,而不针对特定国家。配额可以单方面实施也可以通过谈判,在所谓“自的基础上实施