单选题 The "Karat" marking on jewelry tells you what proportion of gold is mixed with other metals. If 14 parts of gold are mixed with 10 parts of base metal, the combination is called 14 Karat (14K) gold. The higher the Karat rating, the higher the proportion of gold in the object. The lowest Karat gold that can be marketed in the United States is 10-Karat gold. Jewelry does not have to be marked with its Karat quality, but most of it is. If there is a Karat quality mark, next to it must be the U.S. registered trademark of the person or company that will stand behind the mark, as required by the National Gold and Silver Stamping Act.

单选题 If a ring is stamped 24K, it has ______.
A. 204 parts of gold
B. 24 parts of gold
C. two and four-tenths parts of gold
D. 10 parts of gold

【正确答案】 B

【答案解析】[解析] 推断题型。
见文中第二句：If 14 parts of gold are mixed with 10 parts of base metal，the combination is called 14-Karat(14K)gold．如果将14份黄金与10份普通金属混合，它们的化合物即14K金。由此可推论24K金应为24份黄金与10份普通金属混合。所以选项B．“如果一只戒指上刻24K，它应含有24份黄金。”是答案。

单选题 Gold which is 10 Karats in proportion ______ in the U.S.
A. represents the highest grade of gold
B. cannot be sold
C. never carries a Karat quality mark
D. represents the lowest-grade gold marketable

【正确答案】 D

【答案解析】[解析] 细节题型。
见文中：The lowest Karat gold that can be marketed in the United States is 10-Karat gold．能够在美国市场上交易的黄金最低含金量不能低于10K。因此选项D；“10K，的黄金是美国能够上市的最低级别的黄金。”是答案。

单选题 If gold is marked with a Karat quality mark, it must also bear ______.
A. a national gold and silver stamp
B. the registered trademark of the entity standing behind the mark
C. a "made in the USA" mark
D. a percentage mark

【正确答案】 B

【答案解析】[解析] 细节题型。
见文中：If there is a Karat quality mark，next to it must be the U．S．registered trademark of the person or company that will stand behind the mark…如果黄金饰品上标有开/K纯度的质量标志，紧挨这个标志的后面一定要有某个在美国注册的个人或公司的商标。选项B与此同义，故为答案。

单选题 If the jewelry is marked 14 parts of gold mixed with 10 parts of base metal, it will always bear ______ mark.
A. a 14K
B. a 10K
C. an 18K
D. a platinum

单选题 This paragraph serves the consumer as ______.
A. important buying information
B. a challenge to buy more gold
C. a debate over gold prices
D. advice about buying silver

【正确答案】 A

【答案解析】[解析] 推断题型。
本段的主要内容是介绍了K/开的含义，及黄金饰品上应有的标识，因此可推断出它为消费者提供了重要的购买信息。本题也可用排除法做，选项B．“本段为消费者提供了购买更多黄金的挑战。”C．“本段为消费者提供了有关黄金价格的思考。”D．“本段为消费者提供了购买银器的建议。”均不符文中之意。

单选题 The Stamping Act is ______.
A. a regulation for tax
B. rule of law
C. a law that makes such stamping mandate .
D. an implement

【正确答案】 C

【答案解析】[解析] 词义题型。
文中最后一句的Stamping Act指印花税法，即C项所说的“制订印花税授权的法令”，而不是A项所说的税收规则，B项所说的一项法规和D项所说的一种手段。