单选题
The word "smog" has become a household word in urban China. Smog is an
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of greenhouse gases and pollutants that reduce visibility and harm respiratory functions. Smog is typically
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cities with high concentrations of cars and factories. The population density, amount of industry and the fuels used
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together to have an impact on smog levels. During summer, smog is worse
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the production of ozone, the main component of smog, increases in strong sunlight. The important thing to understand about smog is that this kind of pollution is spread out
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large distances.
Walking, biking or using public transportation can help limit ozone production.
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, decreasing household electricity use and keeping your vehicles fuel-efficient reduces
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greenhouse gases. Checking tire pressure, oil levels, air filters, and getting regular maintenance help
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fuel efficiency. Be sure to use only the fuel recommended in the vehicle"s user
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. Simple steps like avoiding stop-and-go traffic and reducing vehicle workload decrease smog-related emissions. To lighten the workload, avoid running the air-conditioner,
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the engine and carrying heavy objects in the vehicle.
【正确答案】
B
【答案解析】由于空白处后面是of greenhouse gases and pollutants，所以要思考哪个选项与污染物连用比较合适。arbitration：裁决；accumulation：积累；optimization：优化；evaluation：评价。显然accumulation最合适。
【正确答案】
D
【答案解析】be accompanied by：伴随着；be obliged to：感谢；be immersed in：专心于(be absorbed in)；be associated with：与……相关。如果一个城市车多厂多，就有可能引发雾霾。be associated with经常用于表示某种现象的原因，如aging associated with lack of sleep。
【答案解析】虽然选项中的四个介词比较简单，但该题的正确答案不容易选择，既要考虑到前面的spread out，又要顾及后面的large distances。词组spread out的含义是“四处扩散”，而large distances表示“距离远”，意味着“覆盖的面积很大”。用between无法修饰large distances，而beneath的意义是“在……下面”，逻辑不通，介词within表示“范围内”，后面的名词通常是一段时间或一定范围内，但over经常表示“遍及”或“覆盖”，如bowls and plates over the table(餐桌上摆满了)或drops of sweat over my face(满脸是汗)。英语介词的用法在短时期内不可能熟练掌握，需要敏锐的观察力和想象力。