第8 題

　　In this passage RDAs refers to ______.

　　A types of vitamins B types of protein C types of minerals D amounts of energy, protein, vitamins, and minerals

　　【正確答案】：D

　　【答案解析】 [分析] 細(xì)節(jié)題型。見(jiàn)文章第三句： RDAs are suggested amounts of calories, protein, and some minerals and vitamins for an adequate diet.選項(xiàng) D 正確，選項(xiàng) A、B、C 都不全面。

　　第9題

　　One implication in this passage is that ______.

　　A all RDAs have been established B not all RDAs have been established yet C it's not important to know RDAs D RDAs are necessary only for sick people

　　【正確答案】：B

　　【答案解析】[分析] 推斷題型。 見(jiàn)文章第二句：These are known as the Recommended Dietary Allowances(RDAs)and are updated regularly based on new research in �？及� www.mokaoba.com nutrition.可知 RDAs 要經(jīng)常更新，所以選項(xiàng)A不對(duì)，選項(xiàng)C、D也披排除：只有選項(xiàng) B 正確。

　　第10 題

　　The reduction of calories in the diet is particularly good for people who suffer from ______.

　　A obesity B premature heart disease and diabetes C high blood pressure and cholesterol levels D all of the above

　　【正確答案】：D

　　【答案解析】 [分析] 細(xì)節(jié)題型。 見(jiàn)第一段最后一句：These suggestions are especially appropriate for people who have other factors for chronic diseases due to family history of obesity，premature heart disease, diabetes, high blood pressure, and high blood cholesterol, or for those who use tobacco.選項(xiàng) A、B、C 三個(gè) 選項(xiàng)都提及到，但只有選項(xiàng) D 最全面，所以 D 正確。

　　第11題 The most popular organic gem is the pearl. A pearl is the response of a marine mollusk to the presence of an irritating impurity accidentally introduced into its body; a cultured pearl is the result of the intentional insertion of a mother-of-pearl bead into a live mollusk. Whether introduced accidentally or intentionally, the pearl-making process is the same: the mollusk coats the irritant with a substance called nacre. Nacre is composed chiefly of calcium carbonate. Because very few natural pearls are now on the market, most pearls used in free jewelry are cultured. These include "Biwa" pearls and most other freshwater pearls. Cultured pearls are not easily distinguished from natural pearls except by an expert. Which of the following people could tell the difference between a cultured pearl and an organic pearl?

　　A Scuba diver. B Fisherman. C Jeweler. D Clerk.

　　【正確答案】：C 【答案解析】 [分析] 細(xì)節(jié)題型。 見(jiàn)文章最后一句：Cultured pearls are not easily distinguished from natural pearls except by an expert.只有專(zhuān)家才能區(qū)分出天然珍珠和人工培 育的珍珠。珠寶商當(dāng)然應(yīng)是這類(lèi)專(zhuān)家，所以選項(xiàng) C 正確。A.Scuba diver 戴水 肺的潛水員 B.Fisherman 漁民和 D.Clerk 職員當(dāng)然不是鑒別珠寶的行家了。

　　第12 題

　　What is the chief component of nacre?

　　A Sand. B Bead. C Calcium carbonate. D Biwa.

　　【正確答案】：C

　　【答案解析】 [分析] 細(xì)節(jié)題型。 見(jiàn)文章第四句：Nacre is composed chiefly of calcium carbonate.選項(xiàng) C.Calcium carbonate(碳酸鈣)正確。

　　第13題 The difference between a pearl and a cultured pearl is the nature of the ______.

　　A color B introduction of the irritating impurity C coating material D irritating impurity

　　【正確答案】：B

　　【答案解析】 [分析] 細(xì)節(jié)題型。 文章第二句(A pearl is the response of a marine„a live mollusk. ) 指出：天然珍珠中的刺激性的雜物是偶然進(jìn)入體內(nèi)的(accidentally introduced into its body);而人工培育的珍珠中的雜物是人為加入的(the intentional insertion);所以選項(xiàng) B 正確。

　　第14題 Nacre is a substance that is ______.

　　A mechanically manufactured B the result of laboratory testing C organically secreted by the mollusk D present in the chemical composition of freshwater pounds

　　【正確答案】：C

　　【答案解析】 [分析] 推斷題型。 文中第三句(Whether introduced accidentally or intentionally, the pearl-making process is the same: the mollusk coats the irritant with a substance called nacre.)說(shuō)明無(wú)論是天然珍珠還是人工：養(yǎng)殖的珍珠，它們 的形成過(guò)程是一樣的：貝類(lèi)用一種被稱(chēng)之為珍珠質(zhì)的物質(zhì)將刺激性的雜物包裹 住。由此推斷出珍珠質(zhì) nacre 是貝類(lèi) the mollusk 滋生分泌出的，所以選項(xiàng) C 正確。

　　第15題 The main idea in this passage is that ______.

　　A most marketable pearls are cultured because nature does not produce enough of its own to satisfy the market B cultured pearls are of a higher quality than natural pearls

　　C there are two major methods of pearl-making D a natural "drought" of pearl production is taking place

　　【正確答案】：C

　　【答案解析】 [分析] 主旨題型。 閱讀全文可知本文介紹了珍珠有天然和人工養(yǎng)殖兩種形成方式，所以選項(xiàng) C 正確。