题目内容
(三)阅读下面短文，回答下列五题。1946年诞生的世界上第一台计算机，体积达90多立方米，重30多吨。后来有了半导体，造出了超大规模集成电路，使电子计算机体积大大减小了。但这种集成电路小型化已接近极限，要在这基础上提高其存储和运算速度也越来越难。由于计算机最基本构件是开关元件，于是专家们设想，假若有机物分子也具备“开”“关”功能，岂不可以造出“有机物计算机”吗后来，科学家发现，半醌类有机化合物分子及蛋白质分子中的氢都具备“开”“关”这两种电态功能。因此，从理论上说，只要用半醌类有机化合物分子或蛋白质分子作元件，就能制造出“半醌型”或“蛋白质型”的计算机。人们把它们称为“生物计算机”或“分子计算机”。生物计算机具有“半永久性”。它有许多优点：一是密集度可达现在集成电路的10万倍；二是运算速度可达半导体开关件的1000倍以上；三是这种由生物分子构成的“生物芯片”也同一般生物一样，具有“自我修复”功能，出了故障可“自我修复”，所以这种生物计算机可靠性高，经久耐用；四是生物元件是用化学能工作，所需能量甚少，不存在元件发热问题。生物计算机的研制始于20世纪60～70年代。美国1983年11月召开了专门学术会议，对生物计算机的研制从理论到实践进行了深入探讨。 日本此项研究由“未来电子仪器科研协会”和通产省指导进行。英国也拨款3000万英镑用于生物计算机的研究开发。目前，生物计算机的研制处于初始阶段，专家们预计，下世纪初叶，可望有突破性进展，并使数字电子计算机产生新的功能。无疑，生物计算机一旦问世，将是计算机科学领域的一次新的革命。 文章第二自然段的“从理论上说”的意思是（）。
查看答案
搜索结果不匹配？点我反馈
更多问题
25岁就诊患者，口腔卫生情况不佳，左下第一恒磨牙患有牙髓一牙周联合病变，疼痛剧烈，但患牙无松动。 另外，还应嘱咐病人做好口腔保健，除了
Every government reform concerning taxes or fees in recent years has given rise to fierce debate in the media and on the Internet. The latest proposed reform of vehicle tax is no exception. The National People’s Congress reviewed proposals on vehicle tax late October. Tax would be based on emissions, or engine size, according to the bill. It suggested raising tax on all vehicles with engines bigger than 1.6 liters. This would mean most car owners would have to pay more once the bill becomes law. Xinhua News Agency has led criticism of the bill. It has published three articles quoting experts questioning the motives and effectiveness of the proposed tax hike. Officials from the Ministry of Finance have said that the tax rise is aimed at encouraging the use of smaller, less-polluting automobiles. They also say that it aims to redistribute wealth. Some support the proposals for they believe by collecting more tax from rich people, the reform could redistribute wealth to some degree. Firstly, if taxes-for large, luxury vehicles increase dramatically but remain the same or lower for smaller vehicles, then naturally people would start buying smaller cars. This helps reduce automobile emissions and leads to a cleaner environment. Secondly, the additional tax revenue could be used to improve benefits for people on lower incomes, to create more jobs and to provide .better education for children from poorer families. This would help them have a better future and would redistribute wealth in society. Finally, automobile consumption in China, especially in large cities, is getting out of hand. Too many cars create serious problems such as pollution, traffic congestion and accidents. Something has to be done to control the number of cars. Heavier taxes would be very effective. Other people disagree with the proposals, for they think that it seems as though the only aim to the tax reform is to increase income for the government. For the first place, compared with the serious wealth gap in Chinese society today, the amount of tax collected on vehicles will make almost no difference in terms of distribution of wealth. Billionaires can buy as many luxury cars as they want but poor people still can’t afford the smallest of cars. Secondly, the majority of privately-owned vehicles in China are in the 1.6 to 2 liter range. This is the most common and economical size for a family car, and is much less polluting than luxury vehicles. However, the new law would almost double the tax levied on these cars. This would not encourage people to buy smaller cars. Finally, the new law does not state where and how the additional tax income from vehicle taxes would be used. We don’t know if the funds will be used to improve benefits for lower-income people, or for other social causes. Which of the following is NOT true
Imagine. One day all of us will have to pay for every breath we take. What will that be like Of course, that’s an exaggeration. But as environmental issues grow more concerning, carbon emissions begin costing more and more to businesses and families. The carbon tax, simply speaking, is an environmental tax charged on fossil fuel. It is based on how much carbon a person or company emits. The primary purpose of such a tax is to lower greenhouse gas emissions. In order to reduce the fees, utilities, business and even individuals attempt to use less energy derived from fossil fuels. Starting in Europe, carbon tax has had a patchy history. It’s widely accepted in Northern Europe, in countries like Denmark, Finland, the Netherlands, Norway and Poland. China, as one of the leading carbon emitters, is also considering levying a carbon tax. This would further boost the price of fossil fuel. "We expect China will start to levy various taxes only if they are helpful in mitigating greenhouse emissions and developing a low- carbon economy," Jiang Kejun, a senior researcher with the Energy Research Institute under the National Development and Reform Commission, told China Daily. "I think a carbon tax is likely to be levied during the 12th Five-Year Plan (2011～2015)," said Jiang. At last year’s Copenhagen Climate Conference, China promised to cut carbon intensity by 40～45 percent by 2020, from 2005 levels. So the government is carrying out "tougher measures" to realize the green goal. According to Jiang, China has already passed the stage of "whether to implement" and is planning on "how to implement". Jiang says that "levying a carbon tax is much more complicated and difficult, especially in the circumstances of China’s economy." Jiang said it might be more practical for China to make a transition from an energy tax to a carbon .tax, like most European countries have done. Still, the consequence of levying a carbon tax undoubtedly would be beneficial. "If the rate of carbon tax is 10 yuan/ton of greenhouse gas emission, as advised, and the carbon emission of burning a ton of coal is 2 tons, this means that the price of a ton of coal will be only 20 yuan higher," said Jiang. "The current price of coal is about 600～800 yuan, so, a carbon tax won’t have much effect on the costs of those enterprises." In the long run, money from levying the carbon tax would be invested in researching and developing new low-carbon energy that can help cut China’s carbon emissions. "Sweden has the highest rate of carbon tax in the world, which is 0.08 euro/kg (0.67 yuan/kg) greenhouse gas," Li Lailai, deputy director of the Stockholm Environment Institute, told Southern Weekly. "Since it’s levied a carbon tax a few years ago, its carbon emission has dropped 3.7 percent from the 1990 level. And its GDP has increased by 25 percent. The numbers tell it all." Taxation and fiscal incentives are just part of a portfolio of possible policy changes in the future. The ultimate goal is to turn China’s low-carbon development pathway into reality. "Apart from a carbon tax, the government may begin to levy environmental and resource taxes. Meanwhile, China will greatly boost subsidies to support low-carbon technology research and development," Jiang said. Suddenly, the word "carbon tax" is coming into our life, even though levying a carbon tax would have a more direct effect on big enterprises than people’s daily life, it’ll still help to better the environment we live in. Let’s do the math. The U. S. now levies a carbon tariff on products exported to the country. The price is $10～70 (68 ～ 478 yuan) a ton of CO2. So, take for example the U. S. pop singer Madonna’s latest world tour. It produced 1,635 tons of carbon emissions, thanks to her private jet, tour bus, and the setting up of stage, lights and other machinery. If a carbon tariff is charged at $ 30 (205 yuan) a ton, she has to pay a $49,050 (334, 968 yuan ) carbon tax. Actress Zhou Xun, an environmental activist, has spent several thousand yuan and bought more than 200 trees to balance out the carbon emission (about 19.5 tons) she produced while traveling last year. So, it seems that a carbon tax is very much related not just to companies and enterprises, but to every one of us. Spend a thousand yuan, and you can buy trees that can counteract about 5.6 tons of carbon emission. That’s the amount of carbon emissions a Chinese family produces in two years. In this case, "paying for breath" doesn’t seem to be so far- fetched an idea after all. The phrase "a patchy history" in Paragraph 3 refers to the fact that ______.
25岁就诊患者，口腔卫生情况不佳，左下第一恒磨牙患有牙髓一牙周联合病变，疼痛剧烈，但患牙无松动。 为了消除病痛，恢复健康，首先采取的措施是
微信支付 
支付宝支付