第1題

　　Which of the following is NOT a type of phytoplankton?

　　A Green algae. B Diatoms. C Blue-green algae. D Amoeba.

　　【正確答案】：D

　　【答案解析】 [分析] 是非題型。 見文章第二段第一句：Marine phytoplankton (Greek for "plant wanderers")are microscopic single-celled plants that include diatoms, dinoflagellates, coccolithophorids, green algae, and blue-green algae, among others.說明海洋浮游生物包括：A.Green algae 綠藻;B.Diatoms 硅 藻屬;C.Blue-green algae 藍綠藻;等等。選項 D.“Amoeba 阿米巴蟲”不包 括在內，所以是答案。

　　第2 題

　　The growth of phytoplankton is often limited by the availability of ______.

　　A oxygen B hydrogen C nitrogen D carbon dioxide

　　【正確答案】：C

　　【答案解析】[分析] 細節(jié)題型。 見文章第二段第二句：The growth of these organisms, which photosynthesize light, depends on a delicate balance of nutrient enrichment via vertical mixing, which is often limited by the availability of nitrogen and light.所以選項 C 正確。

　　第3題

　　The main idea of this passage is that ______.

　　A light causes sea color B sea coloration is varied because of a combination of length of light waves and microscopic plant life and silt C microscopic plant life causes sea color D water composition causes sea color

　　【正確答案】：B

　　【答案解析】 [分析] 主旨題型。 閱讀全文得知，海水顏色的變化是由許多因素決定的;包括選項 A、C、D， 而選項B 是它們的綜合，所以是答案。

　　第4題

　　The United States government publishes guidelines for appropriate nutrient intakes. These are known as the Recommended Dietary Allowances (RDAs) and are updated regularly based on new research in nutrition. RDAs are suggested amounts of calories, protein, and some minerals and vitamins for an adequate diet. For other dietary substances, specific goals must await further research. However, for the U.S. population as a whole, increasing starch and fiber in one's diet and reducing calories (primarily from fats. sugar, and alcohol) is sensible. 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. Snacks can furnish about one-fourth of the calorie requirements among teenagers. Those snacks should also provide much of the day's allowances for protein, minerals, and vitamins. Sandwiches, fruit, and milk make good snacks for active teenagers. Food from the food pyramid may be part of any meal. A grilled cheese sandwich or a bowl of whole-grain cereal is just as nutritious in the morning as it is at noon. In addition, a good breakfast consists of any foods that supply about one-fourth of the necessary nutrients for the day. The passage directly states that most of the U.S. population should increase their intake of ______.

　　A protein B fats C starch and fiber D sandwiches

　　【正確答案】：C

　　【答案解析】 [分析] 細節(jié)題型。 見文章第一段倒數(shù)第二句：However，for the U.S. population as a whole， increasing starch and fiber in one's diet and reducing calories (primarily from fats, sugar, and alcohol) is sensible.選項 C 正確。

　　第5 題

　　A good breakfast should supply about what percentage of the necessary nutrients for the day?

　　A One-half. B One-third. C One-fourth. D Less than one-fourth.

　　【正確答案】：C

　　【答案解析】 [分析] 細節(jié)題型。見文章最后一句：„good breakfast consists of any foods that supply about one-fourth of the necessary nutrients for the day. 選項 C 正確。

　　第6題 The passage implies which of the following?

　　A The time of day when food is consumed affects its nutritive value. B Different foods can be combined to increase total nutrition value. C It can be detrimental to your health to eat breakfast foods later in the day. D When food is eaten has no bearing on its nutritive effects.

　　【正確答案】：B

　　【答案解析】 [分析] 推斷題型。本文第一段第一和第三句介紹：美國政府公布了飲食中合理懾入營養(yǎng)的指導，且建議要有合理的熱量、蛋白質、礦物質和維生素的攝入量;文章第二段第四句 Food from the food pyramid may be part of any meal.說明每頓飯都是由食 物金字塔里的食物構成的。由此推出攝取不同的食物可增加營養(yǎng)價值，選項B正確。

　　第7 題 Why are RDAs regularly updated?

　　A New discoveries in the science of nutrition are constantly being made. B Americans' diets are constantly changing.

　　C As people age, their nutritional needs change. D Very little is currently known about nutrition.

　　【正確答案】：A

　　【答案解析】 [分析] 細節(jié)題型。從文章第二句(These are known as the Recommended Dietary Allowances(RDAs)and are updated regularly based on new research in nutrition. )得知 RDAs 會根據(jù)營養(yǎng)學卜的新發(fā)現(xiàn)經(jīng)常更新推薦的日攝食量。所以“推薦的日攝食量經(jīng)常更新的原因是營養(yǎng)學上經(jīng)常有新的發(fā)現(xiàn)”，選項A正確。