单选题

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.

单选题 The passage directly states that most of the U.S. population should increase their intake of ______.

【正确答案】 C

【答案解析】[分析] 细节题型。见文章第一段倒数第二句：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．选项C正确。

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

单选题 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.

【正确答案】 B

【答案解析】[分析] 推断题型。本文第一段第一和第三句介绍：美国政府公布了饮食中合理慑入营养的指导，且建议要有合理的热量、蛋白质、矿物质和维生素的摄入量；文章第二段第四句Food from the food pyramid may be part of any meal．说明每顿饭都是由食物金字塔里的食物构成的。由此推出摄取不同的食物可增加营养价值，选项B正确。

单选题 Why are RDAs regularly updated?

【正确答案】 A

【答案解析】[分析] 细节题型。从文章第二句(These are known as the Recommended Dietary Allowances(RDAs)and are updated regularly based on new research in nutrition. )得知RDAs会根据营养学卜的新发现经常更新推荐的日摄食量。所以“推荐的日摄食量经常更新的原因是营养学上经常有新的发现”，选项A正确。

单选题 In this passage RDAs refers to ______.

单选题 One implication in this passage is that ______.

【正确答案】 B

【答案解析】[分析] 推断题型。见文章第二句：These are known as the Recommended Dietary Allowances(RDAs)and are updated regularly based on new research in nutrition．可知RDAs要经常更新，所以选项A不对，选项C、D也披排除：只有选项B正确。

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

【正确答案】 D

【答案解析】[分析] 细节题型。见第一段最后一句：These suggestions are especially appropriate for people who have other factors for chronic diseases due to family history of {{U}}obesity{{/U}}，{{U}}premature heart disease, diabetes, high blood pressure, and high blood cholesterol{{/U}}, or for those who use tobacco．选项A、B、C三个选项都提及到，但只有选项D最全面，所以D正确。