| 我国已经开展空气中PM2.5浓度的监测工作．PM2.5是指空气中直径小于或等于2.5微米的颗粒物，其浮在空中很难自然沉降到地面，吸入后会对人体造成危害．下列关于PM2.5的说法正确的是（ ） A．PM2.5在空气中仍受重力作用 B．PM2.5的空间尺度小于电子 C．PM2.5在空气中的运动属于分子热运动 D．PM2.5的密度远大于空气的密度 |
答案：A
| Cloze. | ||||
| The British love to think of themselves as polite, and everyone knows how fond they are of their "pleases" and "thank you". Even the simplest business such as buying a train ticket requires 1 seven or eight of these. Another 2 of our good manners is the queue. New-comers to Britain could be forgiven for thinking that queuing rather than football was the 3 national sport. Finally, of course, motorists generally stop at crossings. But does all this mean that the British should consider themselves more polite than their European neighbours? I think not. Take forms of address (称呼) for example. The average English person- 4 he happens to work in a hotel or department store-would rather die than call a stranger "Sir" or "Madam". Yet in some European countries this is the most basic of common address. Our 5 "you" for everyone may appear more democratic, but it means that we are forced to seek out complicated ways to express 6 . I am all for returning to the use of "thee" and "thou" (Thee and thou are old-fashioned poetic words for "you"); "you" would be 7 for strangers and professional relationships. And of course, the English find touching and other shows of friendship truly terrifying. Have you noticed how the British 8 ever touch? Personally, I find the Latin habit of shaking hands or a friendly kiss quite charming. Try kissing the average English person, and they will either take two steps backwards in horror ; or, if their escape is 9 , you will find your lips touching the back of their head. Now what could be 10 than that? | ||||
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n that he had thrown down. His tracks showed that for two days he had circled in the forest, wit
hin 200 yards of the road. His senses were so dulled by fear and tiredness that he did not hear the cars going by or see the lights at night.
ervation. A skilled woodsman always keeps an eye on his 
surroundings. He notes that the shape of a mountain, the direction water flows through a swamp, and the way a tree leans across a path. With these in mind, he may be turned around many times, but he is seldom lost.
in the forest, at the very beginning, he would __________.