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People are likely to have a higher cholesterol level in winter because
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A scorching sun, an endless sea of sand and a waterless, forbiddingly lonely land—that is the image most people have of deserts. But how true is this picture Deserts are dry lands where rainfall is low. This is not to say rain never falls in deserts: it may fall once or twice a year in a fierce torrent that fades almost as soon as it has begun, or which evaporates in the hot air long before it has got anywhere near the earth. It may fall in a sudden sweeping flood that carries everything in its path. Rains may only come once in five or six years or not fall for a decade or more. The Mojave desert in the United States remained dry for twenty-five years. Without water no living thing can survive, and one feature of the true desert land-scape is the absence of vegetation. With little rain and hardly any vegetation the land suffers under the sun. There are virtually no clouds or trees to protect the earth’s surface and it can be burning hot. Under the sun, soils break up and crack. Wind and torrential rain sweep away and erode the surface further. Eight million square kilometers of the world’s land surface is desert. Throughout history deserts have been expanding and retreating again. Cave paintings show that parts of the Sahara Desert were green and fertile about 10,000 years ago, and even animals like elephants and giraffes roamed the land. Fossil and dunes found in fertile and damp parts of the world show that these areas were once deserts. But now the creation of new desert areas is happening on a colossal scale. Twenty million square kilometers, an area twice the size of Canada, is at a high to very high risk of becoming desert. With a further 1.25 million square kilometers under moderate risk, an area covering 30% of the earth’s land surface is desert, becoming desert, or in danger of becoming desert. The rate of growth of deserts is alarming. The world’s dry lands which are under threat include some of the most important stock-rearing and wheat-growing areas and are the homes of 600～700 million people. These regions are becoming deserts at the rate of more than 58,000 square kilometers a year or 44 hectares a minute. In North Africa at least 100,000 hectares of cropland are lost each year. At this rate there is a high risk that we will be confined to living on only 50% of this planet’s land surface within one more century unless we are able to do something about it. What does the writer think about the creation of new desert areas
There are so many new books about dying that there are now special shelves set aside for them in bookshops, along with the health-diet and home-repair paperbacks. Some of them are so (61) with detailed information and step-by-step instructions for performing the function, that you’d think this was a new sort of (62) which all of us are now required to learn. The strongest impression the casual reader gets is that proper dying has become an extraordinary, (63) an exotic experience, something only the specially trained can do. (64) , you could be led to believe that we are the only (65) capable of being aware of death, and that when the rest of nature is experiencing the life cycle and dying, one generation after (66) , it is a different kind of process, done automatically and trivially, or more "natural", as we say. An elm in our backyard (67) the blight (枯萎病) this summer and dropped stone dead, leafless, almost overnight. One weekend (68) was a normal-looking elm, maybe a little bare in spots but (69) alarming, and the next weekend it was gone, passed over, departed, taken. Taken is right, for the tree surgeon came by yesterday with his (70) of young helpers and their cherry picker, and took it down branch by branch and carted it off in the back of a red truck, everyone (71) . The dying (72) a field mouse, at the jaws of an amiable household cat, is a spectacle I have beheld many times. It (73) to make me wince. However, early in life I gave up throwing sticks (74) the cat to make him drop the mouse, (75) the dropped mouse regularly went ahead and died anyway.
The human brain contains 10 thousand million cells and each of these may have a thousand connections. Such enormous numbers used to discourage us and cause us to dismiss the possibility of making a machine with humanlike ability, but now that we have grown used to moving forward at such a pace we can be less sure. Quite soon, in only 10 or 20 years perhaps, we will be able to assemble a machine as complex as the human brain, and if we can we will. It may then take us a long time to render it intelligent by loading in the right software (软件) or by altering the architecture but that too will happen. I think it certain that in decades, not centuries, machines of silicon (硅) will arise first to rival and then exceed their human ancestors. Once they exceed us they will be capable of their own design. In a real sense they will be able to reproduce themselves. Silicon will have ended carbon’s long control. And we will no longer be able to claim ourselves to be the finest intelligence in the known universe. As the intelligence of robots increases to match that of humans and as their cost declines through economies of scale we may use them to expand our frontiers, first on earth through their ability to withstand environments, harmful to ourselves. Thus, deserts may bloom and the ocean beds be mined. Further ahead, by a combination of the great wealth this new age will bring and the technology it will provide, the construction of a vast, mancreated world in space, home to thousands or millions of people, will be within our power. It can be inferred from the passage that______.
在集装箱运输中，当货主托运危险货物时，在集装箱的外表不需涂刷或粘贴有关危险货物的标志。( )
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