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问题 单项选择题

1到1000的整数(包含1和1000)中至少能被2、3、5之一整除的数共有 (11) 个。

A．668
B．701
C．734．
D．767

答案

参考答案：C

解析： 此题目是容斥原理的应用，具体计算过程如下：
设A表示1到1000的整数(包含1和1000)中能够被2整除的数的集合；B表示1到1000的整数(包含1和1000)中能够被3整除的数的集合；C表示1到1000的整数(包含1和1000)中能够被5整除的数的集合。则问题目标是求取|A∪B∪C|。
根据试题描述，|A|=500，|B|=333，|C|=200，|A∩B|=166，|A∩C|=100，|B∩C|=66，|A∩B∩C|=33。
故|A∪B∪C|=|A|+|B|+|C|-|A∩B|-|A∩C|-|B∩C|+|A∩B∩C|=734。

完形填空

根据句意及所给中文完成以下句子。（20分）

1. I like those students who are careful with their lessons , _________ (例如) Mary , Linda.        

2. ( 事实上 ) ________ ,  the accident caused great damage and a loss of 2 lives.

3. Traveling by train , we visited __________ ( 大量， 许多) cities.        

4. Nowadays , the ____________ ( 受过良好教育的) people have more chances to get employed.     

5. She always ____________ ( 积极参加) all kinds of activities when she was at school.           

6. China ____________ ( 起重要作用 ) international relations.  

7. What about _________ ( 求助于) your teacher for help?           

8. For students , every chance should be __________ (利用) to study hard.

9. He fell off the bike and _________ (受伤了).         

10. He ________ ( 奉献 ) himself to his career and never returned to his homeland.
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选择题

-What do you think of the bottled water?   

-I don't like it at all. It is reported that much nutrition, including some minerals, _____ while it is

 being processed.    [ ]

A. are ridded of  

B. are gotten rid of  

C. gets rid of    

D. is ridded of

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