Withthe(develop)ofindustry,air-优题课

With the ________ (develop) of industry, air pollution _______ (get) more and more serious. In Beijing, many people suffer different kinds of illnesses as a result of air pollution.
Air pollution is caused by the following__________: about half of the problem is caused by transportation. There are more and more cars, buses on the roads, and they give off _________ (harm) gases. 25% of air pollution is caused by factories. Another factor is the smokers. Smoking not only does harm to their health _________ to others. _________ these, about 10% of air pollution is caused by other reasons.
We should take some measures to fight ________ pollution. New fuel can be used to take ________ place of gas. We can plant more trees.__________ everybody realizes the importance of environment and does something to stop pollution, the problem will ________ (solve).

科目英语题型填空题难度中等

知识点：语法填空

将一个电热水器单独接在清零的计量插座上工作 $2 h$ ，屏幕显示如图所示，已知电费单价为0.5元 $/ kW \cdot h$ ，电热水器的功率为　　 $W$ ；若该时间内消耗的电能全部给 $40 kg$ 的水加热（水未沸腾），则水温升高　　 $^{°} C$ 。

$[c_{水} = 4.2 \times 10^{3} J / (kg \cdot^{\circ} C})]$

如图所示，是歼20战机与加油机空中加油的情景，歼20战机相对加油机是　　（选填"静止"或"运动" $)$ 的；由于飞机与空气发生　　而带上了大量的电荷，加油时有燃烧的危险，所以机体上装有尖端放电器。

“沿洄划转如旋风，半侧船头水花没”，这是描写船过漩涡时，漩涡中心流速大，中心的水压　　（选填“大于”或“小于” $)$ 周围的水压而造成的惊险情景；峨眉山顶“煮米不成饭”，是因为峨眉山顶气压　　（选填“高”或“低” $)$ ，水的沸点低造成的。

如图甲所示，阵阵鼓声是鼓面的　　产生的；图乙抽取玻璃罩内空气的过程中铃声变小直至微弱，说明真空　　（选填"能"或"不能" $)$ 传声。

按如图所示电路研究电流与电压的关系。已知电源电压为 $6 V$ ， $R_{1}$ 为定值电阻，滑动变阻器 $R_{2}$ 标有" $20 Ω 1 A$ "字样，电流表量程为" $0 ~ 0.6 A$ "，电压表量程为" $0 ~ 15 V$ "。完成下列问题：

（1）闭合开关后，电流表无示数，电压表示数接近电源电压，出现此故障的原因可能是　　；

（2）若 $R_{1} = 6 Ω$ ，为保证电路安全，滑动变阻器允许连入电路的最小阻值为　　。

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