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问题 单项选择题

狂犬病的主要传染源是

A．野生犬

B．家养犬

C．野生猫

D．家养猫

E．家养兔

答案

参考答案：B

解析：患狂犬病的犬是人感染狂犬病的主要传染源，其次是猫，定期给家养犬接种狂犬病免疫疫苗是控制狂犬病传染源的主要方法。

填空题

（15分）在周期表主族元素中，甲元素与乙、丙、丁三元素上下或左右紧密相邻。甲、乙两元素的原子序数之和等于丙元素的原子序数。这四种元素的最外层电子数之和为20。据此可以推断：

（1）元素甲为_______________，元素丙为_______________。

（2）元素乙和丁所形成化合物的化学式为_______________或_______________。

（3）四元素所形成的化合物相对分子质量最大的是_______________（写化学式），其分子内电子数为__________，它与水反应的化学方程式为__________（只写一个）。
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填空题
从下列方框中选适当的词或短语填空，注意其形式变化。
go through, pack up, communication, face to face, recover from, add up to, set down, get tired
of, get along with, habit
1. The time I spend in doing my homework every day ____ at least three hours.
2. I will ____ your telephone number before I forget it.
3. The robber turned around the corner and found himself ____ with a policeman.
4. She ____ the whole room carefully, but found nothing unusual.
5. "You need to ____ your things in the suitcase quickly," said Mother.
6. How are you ____ your classmates in the new school?
7. She has formed a ____ of playing with her fingers while reading.
8. As is known to all, language is the main means of ____.
9. "I've ___ looking at nature through dirty curtains and dusty windows," Anne told her father.
10. How can Linda ____ her illness in a room which is so dirty and dusty?
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