在自然界中，没有纯粹地带性的自然区域，也没有纯粹非地带性的自然区域。

A. 对
B. 错

虽然距离遥远，但由于历史原因与美国具有文化亲和性的国家是

A. 爱尔兰
B. 德国
C. 法国
D. 中国

The gravity model offers a logical explanation for the fact that

A. trade in services has grown faster than trade in goods.
B. trade in manufactures has grown faster than in agricultural products.
C. Intra-European Union trade exceeds international trade by the European Union.
D. trade between Asia and the U.has grown faster than NAFTA trade.

The gravity model suggests that over time

A. world trade will eventually be swallowed by a black hole.
B. the value of trade between two countries will be proportional to the product of the two countries' GDP.
C. trade between Earth and other planets will become important.
D. trade between all countries will increase.

According to the gravity model, a characteristic that tends to affect the probability of trade existing between any two countries is

A. their cultural affinity.
B. the average weight/value of their traded goods.
C. the distance between them.
D. the number of different product varieties produced by their industries.

Why does the gravity model work?

A. Large economies became large because they were engaged in international trade.
B. Large economies tend to have large incomes and tend to spend more on imports.
C. Large economies have relatively large incomes, and hence spend more on government promotion of trade and investment.
D. Large economies tend to avoid trading with small economies.

根据引力模型，其他条件不变，两个国家间的贸易与两国的GDP成正比，与两国的距离成反比

A. 对
B. 错

加拿大和澳大利亚都是英语国家，人口规模也相当，加拿大多60%，但是相对各自GDP 而言，加拿大的贸易额是澳大利亚的两倍。为什么会如此？

数字信号通过（ ）后可在模拟信道进行传输

A. 编码
B. 解码
C. 调制
D. 解调

模拟信号经过（）后可在数字信道上传输。

A. 编码
B. 解码
C. 调制
D. 解调