试题与答案

观察下列各式:a+b=1;a2+b2=3;a3+b3=4;a4+b4=7;a5+

题型:填空题

题目:

观察下列各式:a+b=1;a2+b2=3;a3+b3=4;a4+b4=7;a5+b5=11;…;则a10+b10=________.

答案:

123

(解法1)由a+b=1;a2+b2=3得ab=-1代入后三个等式中符合,则a10+b10=(a5+b5)2-2a5b5=123.

(解法2)令an=an+bn,易得an+2=an+an+1,从而a6=18,a7=29,a8=47,a9=76,a10=123.

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题型:阅读理解

How much sleep do we need? We are all different. Some people need only three hours of sleep a night. Others need ten hours of sleep a night. Most Americans sleep an average (平均) of seven to eight hours a night. After the age of fifty, the average sleeping time goes down to 6.5 hours a night.

Most people have a bad night when they can’t fall asleep (入睡). The name of this problem is called insomnia.

This isn’t a new problem. Many famous people in history had insomnia, too. Some of these people had special ideas to make them sleep. Benjamin Franklin, the famous inventor, had four beds. He moved(移动) from one to another to fall asleep. King Louis XI V (国王路易十四) of France had four hundred and thirteen beds and hoped to fall asleep in one of them. Mark Twain, the famous American writer, had a different way. He lay on his side across the end of his bed.

小题1:After the age of fifty, the average sleep hours are_______ a night.

A.3 hours

B.7or 8 hours

C.6.5 hours

D.10 hours小题2:Which of the following is TRUE?

A.King Louis XI V was an American.

B.Many famous people in history had a bad night when they couldn't fall asleep.

C.Benjamin Franklin was a famous writer.

D.Most young Americans sleep for an average of 6.5 hours a night.小题3:Why did King Louis XI V of France have more than four hundred beds?

A.Because he hoped to fall asleep.

B.Because he was a famous inventor.

C.Because he had a lot of money.

D.Because he liked to lie on his side across the end of his bed.小题4:What does the word insomnia mean (意思) in Paragraph (段落) 2?

A.too many beds

B.sleep well

C.can’t sleep well

D.problems小题5:What’s Paragraph (段落) 1 talking about?

A.The history of sleep.

B.How much sleep do we need?

C.The story of famous people.

D.Why can’t we sleep?

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题型:问答题

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方案评价参数
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投低标 0.2 70
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不投标 0

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