It is said that about half of the people in China smoke. Many young boys and girls have the habit of smoking, though they are middle school students.
    More and more people have come to realize how serious this problem is. But they are never bored with it. ①Some people think it is a kind of fashion, some think it is of great fun and others think that smoking can relax themselves.
    Smoking causes many illnesses. A lot of people always cough(咳嗽)②______ ______smoking. The most serious illness caused by smoking is lung cancer. At the same time smoking is a waste of money. Beside, careless smokers may cause dangerous fires.
    It's known that smoking does harm to our health. We should get rid of(摆脱) the bad habit of smoking.

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        人类的智慧与大自然的智慧相比实在是相形见绌，无论是令人厌恶的苍蝇蚊子，还是美丽可人的鲜花绿草；无论是高深莫测的星空，还是 a 的灰尘，都是大自然 b 的艺术品，展示出大自然深邃、高超的智慧。大自然用“死”的物质创造了这样丰富多彩的生命，而人类却不能制造出一个哪怕是最简单的生物。就目前所知，人本身就是自然智慧的最高体现，是她最杰出的作品之一。人体共有一万亿多个细胞，这么多的细胞不仅能够相互协调，而且每个细胞都有着 c 的特殊分工、每个细胞都有其特定的工作，绝对不会混淆，从而使整个人体处于高度有序的状态。在近百年的时间中，人体细胞尽管更替许多次，但这种秩序并不会改变。最 d 的恐怕要数我们的大脑了，它使人有喜怒哀乐，能够思维，能够理解、想像。大自然也很“懂得”美学原则，在创造各种物质以至人体的时候运用了各种美的规律，比如对称性、协调性等等，使人体、花朵等表现出难以形容的美。要造出这样的一个人来，让一万亿个细胞协调工作，是人类的智慧所不能胜任的。

2016年3月7日，三明沙县机场成功首航，许多市民乘坐新能源公交车（如图所示）去看机场。公交车满载时的质量为1.2×10⁴kg，车轮与地面总接触面积为0.2m²。（g取10N/kg）

①求满载的公交车静止在水平路面时，对路面的压力和压强大小；

②若该车在5×10³N牵引力的作用下，沿平直路面匀速行驶，40s内通过了600m；

求：牵引力所做的功；牵引力的功率。