化学已经渗透到人类生活的各个方面,下列说法正确的是( )
A．绿色化学的核心是对环境污染进行综合治理
B．烟、云、雾在阳光照射下可观察到丁达尔现象
C．“温室效应”“酸雨”的形成都与氮氧化合物有关
D．高纯度的硅单质广泛用于制作光导纤维,光导纤维遇强碱会“断路”
答案：B
绿色化学是指原料的利用率为100%,A项错误;烟、云、雾属于胶体,光照时可发生丁达尔效应,B项正确;温室效应与CO2有关,C项错误;制作光导纤维的材料是SiO2,D项错误。
| 阅读理解。 | |
An interview with Benno Nigg, the sports scientist
Nigg's Answer: That is a little bit overstated. But the literature shows that shoes are a minor player in injury development. If you take a group of people and want to injure them, send them out every day for a 20-kilometre run. A lot of them will be injured in three weeks. The major factors are the distance run, the intensity and recovery time, not the shoes. 2. _____ Nigg's Answer: The problem is that if you go to a store and want to find your best shoes, you don't know what to do. Things that are sometimes done, like video analysis of your rear foot movement, may not help. The only way to assess whether a shoe is right for you is how it feels. If you feel comfortable in a shoe, it's likely to be good for you. 3. _____ Nigg's Answer: A shoe may act as a training device, making some muscles to function more effectively for a majority of users. Or it may use materials that last longer. That may have something to do with its price. However, for the average runner it is difficult to distinguish between actual functional designs and unnecessary features. Generally, the more a shoe controls movement, the more it acts like a cast, which means you lose some muscle strength, and your feet are more likely to be injured. 4. _____ Nigg's Answer: Yes, for about 80 per cent of people. The major benefits are training the small muscles crossing the ankle joint, and a reduction of knee and lower back pain. However, some claims for these unstable shoes are overstated, such as the general muscle strengthening that they are claimed to produce. 5. _____ Nigg's Answer: There are claims that there are fewer injuries when you run barefoot, but there is not yet enough evidence, or enough research, to prove that. If you look at performance, most papers suggest an advantage of 3 to 4 per cent. With a few exceptions, people don't run barefoot, so it may be that it's not an advantage, or it may be that we're just not used to it. |
