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问题 单项选择题

下面选项中不属于地性线的是（）

A.同脊线

B.同谷线

C.同脚线

D.等高线

答案

参考答案：D

论述题

2008年7月7日至9日，加拿大、法国、德国、意大利、日本、俄罗斯、芙国、英国等八国集团首脑(G8)北海道洞爷湖举行会议。主要议题包括非洲发展、气候变化、世界经济、能源和粮食安全、国际安全领域等问题。中国国家 * * 胡 * * 出席了八国集团同发展中国家领导人对话会议。   

某班探究小组根据这一背景开展探究活动。

(1)材料收集小组负责搜集与会各国政治体制等方面的资料。假如你是该小组成员，请把下表填写完整。(2分)

国家政体国家结构形式
中国民主集中制的人民代表大会制度 
德国 联邦制
美国 联邦制
英国议会制君主立宪制 
(2) 在材料分析小组的讨论中，有的同学认为，上述八国和我国一样都实行代议制，两者没有本质的区别。对此，你作何评价?(8分)

(3)在课堂讨论中同学一致认为我国的政体具有无可比拟的优越性，但仍许多不完善的地方，请你谈谈如何坚持和完善这一政治制度？（4分）
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阅读理解
阅读理解。
A. Causes of overusing fluoride ( 氟化物 )
B. Negative effects of fluoride
C. Safe use of fluoride
D. The expert's background information
E. No need to worry about fluoride poisoning
F. Solutions to improper use of fluoride
     I have heard that fluoride can help stop dental decay, but I recently read that it is poisonous. Which of
these is true? How can children use fluoride safely?
1. ( )
     This question is answered by Dr Marcia M. Rich who practises general dentistry in Newholt. She is also
a lecturer at the University and a writer for the monthly magazine Your Dentist Cares.
2. ( )
     My answer to the first question is to stress that fluoride works well and is safe when users follow
instructions. Young children have a tendency to swallow toothpaste, which is why they should only have a
tiny amount of fluoride toothpaste on their toothbrush. If this simple measure is taken, parents can be
confident that children will be protected against tooth decay, and come to no harm.
3. ( ) 
      Almost all medicines have a negative effect-or even be deadly-if they are not taken as directed. So you
are right-fluoride can be poisonous if it is swallowed in very large quantities. It is for the reason that fluoride
supplements can only be obtained on prescription from the doctor or dentist. Please be assured that fluoride
overdoses are rare-in fact, I have never heard of any fatal incidents related to fluoride poisoning.
4. ( )
     Scientific studies have shown that fluoride can help to prevent cavities(牙洞) as long as it is used
correctly. If fluoride is abused, there is a risk of illness or even deaths in extreme cases. If a deadly amount
of fluoride is taken, immediate first-aid could save a life. A person who has swallowed a large amount of
fluoride will probably start vomiting. If not, the patient should be given milk or antacid and taken to the
nearest hospital for emergency treatment.
5. ( )
     Taking too much fluoride while teeth are growing can lead to a condition called dental fluorosis. The most
likely cause is the swallowing of fluoride toothpastes by young children. It can also be caused by inappropriate
use of fluoride drop or other fluoride supplements, for example when fluoride is already present in drinking
water.
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