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问题 填空题

奥运会田径比赛场上发令枪响后我们看到升起一股白烟，请你写出产生白烟的化学方程式：                            ，其反应基本类型是             。

答案

4P+5O22P2O5   化合反应

题目分析：发令枪的弹丸中含有红磷，红磷在空气中燃烧，生成一种白色固体（五氧化二磷），故能产生大量的白烟，其反应的化学方程式为4P+5O22P2O5；由于该反应是两种物质反应，生成另外一种物质的反应，故属于化合反应。

点评：在解此类方程式的书写题时，首先确定反应原理，然后再依据原理找出反应物、生成物和反应条件，根据方程式的书写规则书写方程式。

阅读理解

阅读理解。

    A couple (夫妇) have travelled around the world in 297 days-without taking any planes Tom Fewins and

Lara Lockwood used 78 buses, 61 trains, 34 cars, 18 boats, six bicycles, and even one elephant. They wanted

to prove that tourists can still be well travelled without damaging the environment. They aimed to product less

than 3,000 kg of carbon dioxide (二氧化痰), compared with six times that amount if they had gone by plane.

    They spent ten months travelling 44,609 miles through l8 countries on land and sea.The couple's world tour

began in June 2008 with a two-hour bus journey to London from their home in Oxfordshire. They took the

train, Eurostar, to Brussels and then caught a bus and train to Hamburg before going to Copenhagen. The

couple even rode on an elephant for l5 miles through the Chinese part of the Mekong River (湄公河).

    The couple hoped to write a book based on their journey to teach other travellers how to travel without

damaging the environment.

根据短文内容回答下列问题。

1.How long did it take the couple to travel around the world?

                                                                                                                                                         

2.Where did the tour begin? 

                                                                                                                                                         

3.How many ways of transportation did the couple use to travel around the world according to the passage? 

                                                                                                                                                          

4.How was the travel different?

                                                                                                                                                          

5.What did the couple hope to do?

                                                                                                                                                           

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多项选择题

对于专用高频通道，在新投入运行及在通道中更换了（或增加了）个别加工设备后，所进行的传输衰耗试验的结果，应保证收发信机接收对端信号时的通道裕量不低于说法错误（），否则不允许将保护投入运行。

A、25dB；

B、1.5dB；

C、8.686dB。
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