托福阅读真题原题+题目（六）

　　PASSAGE 6

　　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 theearly Middle Ages in the making of soap: the former being the product of heating a mixture ofalkali and sand, the latter a product of alkali and vegetable oil. Their importance in thecommunities of colonial North America need hardly be stressed.

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

　　The settlement at Jamestown in Virginia was in many ways a microcosm of the economy ofcolonial North America, and potash was one of its first concerns. It was required for theglassworks, the first factory in the British colonies, and was produced in sufficient quantity topermit the inclusion of potash in the first cargo shipped out of Jamestown. The second ship toarrive 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 waterwas poured over them. The solution draining from the barrel was boiled down in iron kettles. Theresulting 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 foragriculture, for it was estimated that as much as half the cost of clearing land could be recoveredby the sale of potash. Some potash was exported from Maine and New Hampshire in theseventeenth century, but the market turned out to be mainly domestic, consisting mostly ofshipments from the northern to the southern colonies. For despite the beginning of the trade atJamestown 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 thesubstance.

　　1. What aspect of potash does the passage mainly discuss?

　　(A) How it was made

　　(B) Its value as a product for export

　　(C) How it differs from other alkalis

　　(D) Its importance in colonial North America

　　2. All of the following statements are true of both potash and soda EXPECT:

　　(A) They are alkalis.

　　(B) They are made from sea plants.

　　(C) They are used in making soap.

　　(D) They are used in making glass.

　　3. They phrase the latter in line 4 refers to

　　(A) alkali

　　(B) glass

　　(C) sand

　　(D) soap

　　4. The word stressed in line 6 is closest in meaning to

　　(A) defined

　　(B) emphasized

　　(C) adjusted

　　(D) mentioned