英语翻译There are several reasons why governments have often cho

英语翻译
There are several reasons why governments have often chosen to use quotas rather than tariffs as a way of limiting imports.The first is as insurance against further increases in import competition (protectionist insurance) and import spending (balance-of-payment insurance).Quotas help ensure that the quantity of imports is strictly limited.If,for instance,increasing foreign competitiveness lowers the world price of imports,a quota will simply hasten the reduction in the total amount spent on imports.A tariff,by contrast,allows later foreign price cuts to raise both import quantities and (if our demand for imports is elastic) import values,thus complicating any official forecasts of the balance of payments.
Quotas are also chosen in part because they give government officials greater administrative flexibility and power in dealing with domestic firms.These officials usually have discretionary authority over who gets the import licenses under a quota system,and they can use this power to their advantage (e.g.,by taking bribes).For their part,protectionist interests also see a quota system as an opportunity to lobby for special license privileges,whereas a tariff is a source of government revenue to which they do not have easy access.
A quota operates by limiting the physical amount of the good or service imported.This reduces the quantity available to consumers,which in turn causes the domestic price to rise.The domestic price continues to rise until the quantity supplied domestically at the higher price plus the amount of the import allowed under the quota exactly equals the reduced quantity demanded.The quota thus restricts quantity supplied,causing price to adjust,in contrast to a tariff,which induces a quantity adjustment by fixing a higher domestic price.

政府常常采用限额而不是关税来限制进口是有几个原因的.首先,这是进口竞争增长（保护主义者的措施）和进口花费（国际收支保护措施）的保险措施.限额有利于确保进口的数量是被严格限制的.举个例子,如果不断增长的国外竞争力使得进口价格降低,限额制度就会促进在进口总值上的锐减.相比之下,关税使之后的国外产品降价,以增长了进口数量和（如果我们的进口需要是弹性变化的）进口值,而使政府对于贸易支付差额的预测复杂化.
其次,限额制也常常能给政府机关更大行政上的弹性空间,以及处理国内公司事务上的权力.在限额制制度下,这些官员常常拥有可自由决定权——决定哪些公司拥有进口执照,他们可以利用这些权力为自己谋求利益（比如受贿）.对他们而言,保护主义势力仍然把限额制制度看作一个为执照特权游说的机会,而关税则是一种他们不能轻易接近的国家收入.
一种配额制度的执行依赖于对进口货物（或服务）实际数量的限制.这就降低了消费者能买到的该产品的数量,相应地提高了国内产品的价格.国内价格会持续上升,直到高价供应的产品数量加上在配额制下允许进口的产品数量等于要求降低的数量.此外,相比依靠确定一个更高的国内价格来调整数量的关税,配额制可以依靠限制数量上的供应,导致价格的调整.