题目内容
A (36) of the physical and chemical nature of life must begin, not on the Earth, but in the Sun. In fact, it is at the Sun’s very center. It is here that is to be found the source of the energy that the Sun (37) pours out into space as light and heat. This energy is liberated at the center of the Sun as billions upon billions of nuclei of hydrogen atoms (38) with each other and fuse together to form nuclei of helium (氦). And, in doing so, it (39) some of the energy that is stored in the nuclei of atoms. The output of light and heat of the Sun requires that some 600 million tons of hydrogen be (40) into helium in the Sun every second. This the Sun has been doing for several thousands of millions of years. The nuclear energy is released at the Sun’s center as high-energy gamma (41) , a form of electro-magnetic radiation like light and radio waves, only of very much shorter (42) This gamma radiation is (43) by atoms inside the Sun, to be re-emitted at slightly longer wavelengths. This radiation, in its turn, is absorbed and re-emitted. (44) , it passes through the X-ray part of the spectrum (频谱), eventually becoming light. At this stage, it has reached what we call: the solar surface and can escape into space, (45) A very small fraction of the Sun’s light and heat is emitted in such directions (46) .
查看答案
搜索结果不匹配？点我反馈
更多问题
Fears of "mad cow" disease spread (1) the globe last week (2) South Africa, New Zealand and Singapore joining most of Britain’ s European Union partners in (3) imports of British beef. In London, steak restaurants were empty follwing the March 20 announcement by scientists that they had found a (4) link between mad cow disease from British beef and its human (5) , Creutzfeldt-Jakob disease(CJD) . Efforts to reassure consumers and governments proved (6) . France, Germany, Italy, Finland and Greece were among countries which announced bans (7) British beef shipments. A committee of EU veterinary experts, meeting in Brussels, (8) new protective measures but said transmission of the disease from cattle to humans was unproven and did not (9) a general ban on British beef exports. Britain’s own main consumer group advised people to (10) beef if they wanted to be absolutely sure of not (11) CJD which destroys the brain and is always (12) . "Could it be worse than AIDS" The stark headline in Friday’s Daily mail newspaper encapsulated the fear and uncertainty (13) Britain. CJD (14) humans in the same way that BSE makes cows mad—by eating away nerve cells in the brain (15) it looks like a spongy Swiss cheese. The disease is incurable. Victims show (16) of dementia and memory loss and usually die (17) six months. Little is known (18) sure about the group of diseases known collectively as spongiform encephalopathies, which explains (19) some eminent scientists are not prepared to (20) a human epidemic of AIDS-like proportions.
某固定资产项目投产，投资500万元，建设期一年，建设资金于建设起点投入300万元，建设期末投入200万元，运营期为10年，终结点回收固定资产残值50万元。该项目投产后，每年可获利80万元，假定行业基准折现率为10%。 要求：计算该项目的投资净现值，净现值率和获利指数。 [(P/A，10%，10)=6.1446，(P/F，10%， 11)=0.3505，(P/A，10%，1)=0.9091]
Text 2 The producers of instant coffee found their product strongly resisted in the market places despite their product’s manifest advantages. Furthermore, the advertising expenditure for instant coffee was far greater than that for regular coffee. Efforts were made to find the cause of the consumers’ seemingly unreasonable resistance to the product. The reason given by most people was dislike for the taste. The producers suspected that there might be deeper reasons, however. This was confirmed by one of motivation research’s classic studies, one often cited in the trade. Mason Haire, of the university of California, constructed two shopping lists that were identical except for one item. There were six items common to both lists: hamburger, carrots, bread, baking powder, canned peaches, and potatoes, with the brands or amounts specified. The seventh item, in fifth place on both lists, read "1 lb. Maxwell House Coffee" on one list and "Nestle Instant Coffee" on the other. One list was given to each one in a group of fifty women, and the other list to those in another group of the same size. The women were asked to study their lists and then to describe, as far as they could, the kind of women ("personality and character") who would draw up that shopping list. Nearly half of those who had received the list including instant coffee described a housewife who was lazy and a poor planner. On the other hand, only one woman in the other group described the housewife, who had included regular coffee on her list, as lazy; only six of that group suggested that she was a poor planner. Eight women felt that the instant-coffee user was probably not a good wife! No one in the other group drew such a conclusion about the housewife who intended to buy regular coffee. Which of the following was confirmed by the motivation studies
“海关放行”是指海关在接受各类进出口货物的申报，经过审核报关单证、查验货物、依法征收税费，作出结束海关监管，允许货物自由处置(或自由流通)的决定的行为。( )
微信支付 
支付宝支付