问题 选择题

身高互不相同的4个人排成2横行2纵列,在第一行的每个人都比他同列的身后的人个子矮,则所有排列数是(  )

A.4

B.6

C.8

D.12

答案

要使的第一行的每个人都比他同列的身后的人个子矮,

只要从四个人中选出2个,两个人的身高就是确定的,不用排列,

剩下的两个人的身高也是确定的,

∴共有C42=6种结果,

故选B.

阅读理解

The weather is getting gotter. You are thirsty after playing basketball or riding home from School. A cold drink may be just the thing. But be careful of what you are drinking. Something that looks cool may not be good for our health. There are plenty of "energy drinks" on the market. Most of

them have beautiful colors and cool names. The lists on them tell you they are helpful to your health. Sounds great!

But after a careful check you may find that most energy drinks have lots of caffeine (咖啡因) in them. These drinks are especially aimed at young people, students, busy people and sports players. Makers sometimes say their drinks make you better at sports and can keep you awake. But be careful not to drink too much.

Caffeine makes your heart beat fast. Because of this, the International Olympic Committee has limited( 限制) its use. Caffeine in most energy drinks is at least as strong as that in a cup of coffee or tea. Possible health dangers have something to do with energy drinks. Just one box of energy drink can make you nervous, have difficulty sleeping and can even cause heart problems. Scientists say that teenagers should be discouraged from taking drinks with a lot of caffeine in them.

小题1:Many people like drinking energy drinks because of the following EXCEPT that ________.

A.they have beautiful colors and cool names

B.they have lots of caffeine

C.they can keep them awake and better at sports

D.they are said to be helpful to health小题2:The main reason for people not to drink too much energy drinks is that they may cause _____.

A.heart problems

B.nervousness

C.sleeping difficulty

D.possible health dangers小题3:Which of the following can take the place of the underlined word “discouraged

A.encouraged

B.stopped

C.helped

D.disliked小题4:From the passage we can know that _________.

A.advertisements are important in getting people to buy energy drinks

B.energy drinks are helpful to teenagers' study

C.sports players need to drink a lot of energy drinks

D.energy drinks are especially aimed at teenagers小题5:The best title of the passage is ________.

A.Engergy Drinks Are Useful

B.Energy Drinks Help Teengagers

C.Energy Drinks--- Be careful

D.Energy Drinks---Good for Health

名词解释