阅读理解

Directions: There are 3 passages in this part. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A, B, C and D. You should decide on the best choice and write the answer on the Answer Sheet.


Passage Two

Potash (the old name for potassium carbonate) is one of the two alkalis (the other being soda, sodium carbonate) that were used from remote antiquity in the making of glass, and from the early Middle Ages in the making of soap: the former being the product of heating a mixture of alkali and sand, the latter a product of alkali and vegetable oil. Their importance in the communities of colonial North America need hardly be stressed.

Potash and soda are not interchangeable for all purposes, but for glass- or soap-making either would do. Soda was obtained largely from the ashes of certain Mediterranean sea plants, potash from those of inland vegetation. Hence potash was more familiar to the early European settlers of the North American continent.

The settlement at Jamestown in Virginia was in many ways a microcosm of the economy of colonial North America, and potash was one of its first concerns. It was required for the glassworks, the first factory in the British colonies, and was produced in sufficient quantity to permit the inclusion of potash in the first cargo shipped out of Jamestown. The second ship to arrive in the settlement from England included among its passengers experts in potash making.

The method of making potash was simple enough. Logs was piled up and burned in the open, and the ashes collected. The ashes were placed in a barrel with holes in the bottom, and water was poured over them. The solution draining from the barrel was boiled down in iron kettles. The resulting mass was further heated to fuse the mass into what was called potash.

In North America potash making quickly became an adjunct to the clearing of land for agriculture, for it was estimated that as much as half the cost of clearing land could be recovered by the sale of potash. Some potash was exported from Maine and New Hampshire in the seventeenth century, but the market turned out to be mainly domestic, consisting mostly of shipments from the northern to the southern colonies. For despite the beginning of the trade at Jamestown and such encouragements as a series of acts “to encourage the making of potash,” beginning in 1707 in South Carolina, the softwoods in the South proved to be poor sources of the substance.

单选题 What aspect of potash does the passage mainly discuss?
【正确答案】 D
【答案解析】本题考查对于主旨大意的理解。在第一段末尾作者提出很少有人强调碳酸钾对于北美殖民地的重要性。第二段解释碳酸钾为什么对于北美洲的欧洲定居者来说很熟悉。后面三段分别介绍了碳酸钾在北美洲的不同用途以及制法。因此本文主要探讨碳酸钾对于北美殖民地的重要性。
单选题 All of the following statements are true of both potash and soda EXPECT _____.
【正确答案】 B
【答案解析】由全文第一句话“Potash is one of the two alkalis …the other being soda”可知碳酸钾和碳酸钠同属于碱类。这句话后半部分提到碳酸钾即可用于制造玻璃也可用于制造肥皂。选项ACD的表述均符合原文。
单选题 It can be inferred from the passage that potash was more common than soda in colonial North America because _____.
【正确答案】 A
【答案解析】文章第二段第二句提到“碳酸钠可由地中海海洋植物的灰烬中提取,而碳酸钾则是从内陆植物中提取。因此碳酸钾对于北美殖民地中的欧洲定居者来说很熟悉”,因此选项A的表述符合原文。
单选题 According to paragraph 4, all of the following were needed for making potash EXCEPT _____.
【正确答案】 C
【答案解析】根据文章第四段第二、三句“Logs was piled up and burned in the open…and water was poured over them”可知碳酸钾的制造过程中需要用到木头,火以及水。故选C。
单选题 According to the passage, a major benefit of making potash was that _____.
【正确答案】 B
【答案解析】根据第五段第一句可知:在北美生产碳酸钾能够迅速帮助农业清理田地,清理田地的一半成本来自于生产碳酸钾的利润。