未知题型 As you know, 'being green' means that you care about the environment (环境) and that you do what you can to help the Earth. Recycling (回收利用) paper and cans, reducing waste, and protecting wildlife are all examples of 'green' activities.This special green issue of National Geographic Kids is devoted to environment. In fact, you're being green simply by reading it. When you're finished, you'll know a lot of things you probably didn't know at all. And you'll be a greener citizen with a strong sense of environmental protection.In this issue(一期杂志) you will discover how you can help the Earth face its five biggest environment problems. Animal behavior. specialist Jane Goodall shares new ideas about how you can help wildlifE.Answer actor Leonarde DiCaprio's call to action to help the environment. Just how green are you? Answer actor questions on Page 10 to find out. You may win a trip to Orlando, FloridA.And there's a special pullout poster to hang on the wall.The writer's main purpose in writing this text is to ______.A.persuade the reader to waste lessB.explain the meaning of the word 'green'C.encourage people to buy this issueD.call on people to protect the environment

单项选择题 客服为买家甄选物流方式时选择国际物流方式运费越低越好

单项选择题 应征进口税税额在人民币50元（含50元）以下的，海关予以免征

多项选择题 以下属于产生未焊透和未熔合缺陷的因素有（     ）。A. 电弧热输入过大B. 焊接电流过小C. 焊接速度过高D. 电弧产生磁偏吹

未知题型 When Charles Darwin explained evolution (进化), the process he saw was natural selection (选择). It turns out human selection can also cause plants to evolvE.Take the case of the snow lot us, a rare (稀小的) plant that grows only high up in the Himalayas. Researchers have discovered that type of the plant has been becoming smaller over time—the one people like to pick.A type of snow lotus called Saussurea Laniceps is used in Tibetan and Chinese medicine and is increasingly demanded by tourists. The largest plants are picked, and that occurs during their only flowering perioD.The result is that only smaller, unpicked plants go to seeD.Selection caused by human beings is a powerful force, according to some scientists. They studied the plants picked over time and also compared the snow lotuses growing in heavily harvested areas with those found in places where people rarely picked them.They reported in an article that the heavily harvested snow lotuses have been getting shorter over the last century, while those in areas not picked have remained the samE.They found that in the heavily harvested areas, where only the smaller plants got to reproduce, the average height was 5.3 inches. The same plants in rarely harvested areas averaged 9 inches in height. And they noted that another type of snow lotuses which is not often picked, has not been changing.What does the word 'that'(Line2, ParA.3) refer to?A.Research done by Darwin.B.Seeds of Saussures Laniceps by natual selection.C.The picking of Saussures Laniceps by tourists.D.The Saussures Laniceps used in traditional Chinese medicinE.