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第二部分
有人 (155) 算过一个人一生中，这样那样的零星杂事得花去多少时间。 (156) 如人的平 (157) 年龄是70岁，那就是说可以活25000余天。要是一个人每天用于 (158) 牙、修面、淋浴的时间约20分钟，那么他一生用于这些事的时间 (159) 共要一年左右。至于睡觉一 (160) 至少得用去 20年的时间。

答案

参考答案：均

探究题

在“研究自行车上摩擦”的活动后

（1）小明了解到在_________时，是要通过增大压力的方法增大摩擦的；而在车轴内安装滚珠轴承则是通过_________________的办法减小摩擦的。

（2）小明和小华还对自行车的前进问题进行了讨论，小明问：“使自行车前进的动力是哪儿来的呢？”小华说：“我认为人脚蹬脚踏的力是自行车前进的动力。”就探究过程而言，小华的看法属于_______。

（3）小明不同意小华的观点，但也不知道怎样说服小华，于是他们一起去请教物理老师。老师找来一辆自行车，支起它的后撑后（如图），老师让小华骑上车并使劲蹬脚踏。小华下来后，老师又手拿一张纸，慢慢靠近还在转动的车后轮的底部，看到纸片不断地被车轮向后推出。

①上述实验说明，用力蹬脚踏________（选填“能”或“不能”）使自行车前进。

②因为人踩脚踏而转动的后轮会对地面产生向______的推力，由于物体间力的作用是_____的，所以自行车获得了前进的动力，这个动力的施力物体是_________。 

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阅读理解
阅读理解。
     Su Hua is studying at Cambridge, UK. She has bought a bicycle and is worried about security (安全).
Her friend, Kate, found this article and sent it to her.
Introduction
A lot of crime is against bicycles. About 150,000 bicycles are stolen every year
and most are never found. You can prevent this happening by following a few
careful steps.
Basic Security
Do not leave your bicycle in out-of-the-way places. Always lock your bicycle when you leave. Secure it to lampposts or trees. Take off smaller parts and
take them with you, for example lights and saddles (车座).
Locks
Get a good lock. There are many different types in the shops. Buy one that
has been tested against attack. Ask for a recommendation from a bike shop.
Marking
Security marking your bike can act a deterrent to a thief. It can also help the
police find your bicycle. It should be clearly written and include your postcode and your house or flat number. This will provide a simple way to identify your bicycle.
Registration
There are a number of companies who will security mark your bicycle for you. They will then put your registration number and personal details on their
computer database. Then if your bicycle is found it will be easy to contact you.
Finally
Keep a record of the bicycle yourself: its make, model and registration number. You can even take a photograph of it. This will prove the bicycle belongs to
you.
1. Which part of the text gives you information on how to lock up your bicycle when you leave it?
A. Locks.
B. Marking.
C. Registration.
D. Basic Security.
2. The underlined phrase "act as a deterrent to a thief" means _____.
A. help you recognize your bike
B. help the police find your bicycle
C. stop someone stealing your bicycle
D. stop you worrying about your bike
3. The article advises you to keep a record of your bicycle ______.
A. in the bike shop and your computer
B. in the police station and a security company
C. in a security company and your university
D. by yourself and in a security company
4. The main purpose of this article is _____.
A. to tell you what to do if your bicycle is stolen
B. to suggest ways of keeping your bicycle safe
C. to give you advice on where to buy a good lock
D. to say why you shouldn't keep your bicycle in a quiet place
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