问题 单项选择题

下列关于字节的4条叙述中,正确的一条是

A.字节通常用英文单词“bit”来表示,有时也可以写做“b”

B.目前广泛使用的Pentium机其字长为5个字节

C.计算机中将8个相邻的二进制位作为一个单位,这种单位称为字节

D.计算机的字长并不一定是字节的整数倍

答案

参考答案:C

解析: 选项A:字节通常用Byte表示。选项B:Pentium机字长为32位。选项D:字长总是8的倍数。

问答题 简答题
单项选择题

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.

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