问题 选择题

下列各组中的元素用原子序数表示,其中都属于主族的一组元素是( )

A.2,4,6

B.19,20,21

C.1,3,5

D.8,16,18

答案

答案:C

题目分析:A.2是He是0族元素,4是Be是第ⅡA的元素,6是C是第ⅣA的元素,错误;B.19,20,21 是第四周期的不同族的元素,21是副族元素,错误;C.1,3是第IA主族的元素,5是第ⅢA主族的元素,同属于主族 ,正确;   D.8,16,是第ⅥA的元素,18 是0族元素,错误。

阅读理解

Will it matter if you don’t take your breakfast? A short time ago, a test was given in the US. People of different ages, from 12 to 83, were asked to have a test. During the test, these people were given all kinds of breakfast, and sometimes they got no breakfast at all. Scientists wanted to see how well their bodies worked when they had eaten different kinds of breakfasts.

The results show that if a person eats a right breakfast, he or she will work better than if he or she has no breakfast. If a student has fruit, egg, bread and milk before going to school, he will learn more quickly and listen more carefully in class.

The result is opposite to what some people think. Having no breakfast will not help you lose weight(减轻体重).This is because people become so hungry at noon that they eat too much for lunch. They will gain weight (增加体重 )instead of losing it. You will lose more weight if you reduce your other meals.

小题1:During the test, the people were given __________.

A.no breakfast at all

B.different foods or sometimes none

C.very rich breakfast

D.little food for breakfast小题2:The results show that _________.

A.breakfast has great effect (影响) on work and studies.

B.breakfast has little to do with a person’s work

C.a person will work better if he only has fruit and milk.

D.girl students should have little for breakfast.小题3:According to the passage, some people think that if you don’t have breakfast you will _______.

A.be healthier

B.work better

C.lose weight

D.lose your way小题4: The word “reduce” in the last sentence means_________

A.增加

B.减少

C.放弃

D.享用

单项选择题