咩叫關稅牙@@?

關稅是指國家授權海關對出入關境的貨物和物品徵收的一種稅。關稅在各國一般屬於國家最高行政單位指定稅率的高級稅種，對於對外貿易發達的國家而言，關稅往往是國家稅收乃至國家財政的主要收入。
依照收稅的方式，一般分為三種：進口關稅、出口關稅、特別關稅。 進口關稅是指對進口貨物和物品徵收的稅

從價稅：依照進出口貨物的價格作為標準徵收關稅。
從量稅：依照進出口貨物數量的計量單位（如「噸」、「箱」、「百個」等）徵收定量關稅。
混合稅：依各種需要對進出口貨物進行從價、從量的混合征稅。
滑準稅：關稅稅率隨著進口商品價格由高到低而由低到高設置的稅。可以起到穩定進口商品價格的作用。
依照徵收關稅的目的，關稅也可分為：

以增加國家財政收入為主的財政關稅。
為保護國內經濟行業而徵收的保護關稅。其中隨著經濟全球化的發展，一國政府可以在其國內市場受到某種外國商品的傾銷時，為保護本國相關行業而臨時徵收保護關稅中的反傾銷稅。
既具有增加國家收入，又以保護本國經濟為主的關稅為混合關稅。
此外，依照過關貨物的流向可以分為進口稅、出口稅、過境稅和各種形式的優惠關稅與差別關稅。

[編輯] 作用
徵收關稅是一國政府增加其財政收入方式之一，但隨著世界貿易的不斷發展，關稅占國家財政收入的比重在不斷下降。
每個國家都會對進出口的商品根據其種類和價值徵收一定的稅款。其作用在於通過收稅抬高進口商品的價格，降低其市場競爭力，減少在市場上對本國產品的不良影響。
關稅有著保護本國生產業的作用，但在經濟全球化的今天其不利的影響也在逐步顯現。

A tariff is a tax on foreign goods. When a ship arrives in port a customs officer inspects the contents and charges a tax according to the tariff formula. Since the goods cannot be landed until the tax is paid it is the easiest tax to collect, and the cost of collection is small. Smugglers of course seek to evade the tariff.

An ad valorem tax is a percentage of the value of the item, say 10 cents on the dollar, while a specific tariff is so-much per weight, say $5 per ton.
A "revenue tariff" is a set of rates designed primarily to raise money for the government. A tariff on coffee exports, for example (imposed upon countries which do not grow coffee) raises a steady flow of revenue.
A "protective tariff" is intended to artificially inflate prices of imports and "protect" domestic industries from foreign competition (see also effective rate of protection). For example, a 50% tax on a machine that importers formerly sold for $100 and now sell for $150. Without a tariff the local manufacturers could only charge $100 for the same machine; now they can charge $149 and make the sale.
A prohibitive tariff is one so high that no one imports any of that item.
The distinction between protective and revenue tariffs is subtle: protective tariffs in addition to protecting local producers also raise revenue; revenue tariffs produce revenue but they also offer some protection to local producers. (A pure revenue tariff is a tax on goods not produced in the country, like coffee perhaps.)

Tax, tariff and trade rules in modern times are usually set together because of their common impact on industrial policy, investment policy, and agricultural policy. A trade bloc is a group of allied countries agreeing to minimize or eliminate tariffs against trade with each other, and possibly to impose protective tariffs on imports from outside the bloc. A customs union has a common external tariff, and, according to an agreed formula, the participating countries share the revenues from tariffs on goods entering the customs union.

If a country's major industries lose to foreign competition, the loss of jobs and tax revenue can severely impair parts of that country's economy. Protective tariffs have been used as a measure against this possibility. However, protective tariffs have disadvantages as well. The most notable is that they increase the price of the good subject to the tariff, disadvantaging consumers of that good or manufacturers who use that good to produce something else: for example a tariff on food can increase poverty, while a tariff on steel can make automobile manufacture less competitive. They can also backfire if countries whose trade is disadvantaged by the tariff impose tariffs of their own, resulting in a trade war and disadvantaging both sides.

There are two main ways of implementing a tariff:

An ad valorem tariff is a fixed percentage of the value of the good that is being imported. Sometimes these are problematic as when the international price of a good falls, so does the tariff, and domestic industries become more vulnerable to competition. Conversely when the price of a good rises on the international market so does the tariff, but a country is often less interested in protection when the price is higher. They also face the problem of transfer pricing where a company declares a value for goods being traded which differs from the market price, aimed at reducing overall taxes due.
A specific tariff is a tariff of a specific amount of money that does not vary with the price of the good. These tariffs may be harder to decide the amount at which to set them, and they may need to be updated due to changes in the market or inflation.
Adherents of supply-side economics sometimes refer to domestic taxes, such as income taxes, as being a "tariff" affecting inter-household trade.

關稅
customs duties; tariff duties

(duty to be paid when the goods transport from place A to place B)