单选题 近年来，中国航天工业取得了巨大的进步。去年是中国航天的关键一年。这一年里中国航天发生了两件大事。其一就是中国发射了嫦娥四号月球探测器(probe)，使中国成为世界上首个在月球背面实现着陆的国家。另一件就是长征五号火箭发射成功，因为长征五号是中国新一代运载火箭，也是中国运载能力最大的火箭。长征五号火箭的成功发射将会为中国更多太空探险任务铺平道路。

单选题One ought ______ for what one hasn't done. A. not to be punished B. to not be punished C. to not punished D. not be punished

单选题Accommodations must be made for students with learning disabilities.

单选题The newcomer was ______ admittance to the classroom for not being properly dressed. A. rejected B. denied C. opposed D. refused

单选题Your story about the frog turning into a prince is ______ nonsense.

单选题It was a long time before the cut on my hand______ completely.

单选题Assuming that a constant travel-time budget, geographic constraints and short-term infrastructure constraints persist as fundamental features of global mobility, what long-term results can one expect? In high-income regions, (21) North America, our picture suggests that the share of traffic (22) supplied by buses and automobiles will decline as high-speed transport rises sharply. In developing countries, we (23) the strongest increase to be in the shares first for buses and later for automobiles. Globally, these (24) in bus and automobile transport are partially offsetting. In all regions, the share of low-speed rail transport will probably continue its strongly (25) decline. We expect that throughout the period 1990～2050, the (26) North American will continue to devote most of his or her 1.1-hour travel-time (27) to automobile travel. The very large demand (28) air travel (or high-speed rail travel) that will be manifest in 2050 (29) to only 12 minutes per person a day; a little time goes a long way in the air. In several developing regions, most travel (30) in 2050 will still be devoted to nonmotorized modes. Buses will persist (31) the primary form of motorized transportation in developing countries for decades. (32) important air travel becomes, buses, automobiles and (33) low-speed trains will surely go on serving vital functions. (34) of the super-rich already commute and shop in aircraft, but average people will continue to spend most of their travel time on the (35) .

单选题Black FridayEveryone likes to shop for gifts for the holiday season, but few people know the history of holiday shopping. While people have heard of Black Friday; most do not know its origins. Black F

单选题When the opposing player fouled John, John let his anger ______ his good sense and hit the boy back.

单选题 How to Cure Jet Lag A. Jet lag is exhausting, disorientating, and can even make you lose your appetite. B. According to Air Space magazine the term 'jet lag' may have been first coined in February 1966. 'If you're going to be a member of the Jet Set and fly off to Katmandu for coffee with King Mahendra,' wrote Horace Sutton in the Los Angeles Times, 'you can count on contracting Jet Lag, a debility like a hangover. Jet Lag derives from the simple fact that jets travel so fast they leave your body rhythms behind.' C. It's only in the last few decades that humans have been able to jump time zones, and we've yet to find a way to adapt. But what actually happens to our bodies when we leap across time zones and how is research helping us understand how to ease the effects? D. Jet lag is the result of a disruption in our body's internal clocks. Our biological clocks drive our circadian rhythms (生理节奏), which anticipate dawn and dusk, and controls everything from blood pressure to how hungry we are. The system is a 'master clock' in our brain that is sensitive to our exposure to light coordinates all the body clocks within our organs and tissues. E. It takes most people a few days to fully adjust, depending on not only how many time zones have been crossed, but also the direction of travel. Adjusting to eastward travel is harder because of the way our internal body clock functions. As this clock follows a period of just over 24 hours, our bodies compensate every day by contracting this to keep up with the regular 24-hour sun cycle. When you travel west, you gain several hours, and so your body has extra time to make this adjustment. Travel east, though, and your day is shortened, which makes the adjustment more difficult. Shift work F. So how possible is it to fool our biological clocks? 'There is no silver bullet—so far—to treat jet lag,' says Horacio de la Iglesia, professor of biology at the University of Washington. 'Typically, the best way involves a combination of strategies that include restricting light exposure to specific times, restricting rest and meals, as well as activities such as walking and running to specific times.' Simon Archer from Surrey University agrees, at least in principle. 'A combined approach can be helpful, but in practice it may be difficult to get all the timings right—it may be very difficult not to be exposed to light at an inappropriate time.' G. All these strategies are aimed at speeding up the adjustment of our multiple clocks to the new time zone. Work over the past 15 years has led to an amazing increase in our understanding of the circadian clock, light input and jet lag, says Stuart Peirson of the Nuffield Laboratory of Ophthalmology at Oxford University. H. Together with his team, he has been studying how light changes the expression of clock genes in the SCN. Increased expression of certain clock genes effectively moves the molecular 'hands' of the clock to the correct time, says Peirson—but there seems to be a limit on how much the clock can be shifted: it's just one hour per day. 'Our work in this area has identified a natural brake—a protein called SIK1—that is activated by light and actively prevents the clock shifting. Normally it would take five or six days to adjust to a six-hour shift in time zone. 'When this [SIK1] mechanism is blocked, it enables mice to shift their clocks much more quickly—shifting six hours in two-to-three days,' says Peirson. Be prepared I. Some scientists are looking at how we can avoid jet lag by preparing for it in advance. 'We believe it is important for many people to start the process of shifting your internal rhythms before the flight, so that you arrive with little or no jet lag,' says Charmane Eastman at Rush University in Chicago, Illinois. 'Most recommendations and computer-based programs only make recommendations for what to do after landing in the new time zone.' J. Together with colleagues, Eastman has been investigating how people could reset their body clocks before flying. Speed shift K. There might also be ways to adjust the body clock without drugs. Another group of scientists has designed an app called Entrain that uses mathematical modelling to determine how our body can shift from one time zone to another in the quickest way possible. If users type in the timezone they are travelling to, the app calculates a schedule that tells the user when they should expose themselves to light. L. The researchers say it's probably easiest for travellers to divide their day into two parts, one where they seek as much light as possible and another where they should try to be in darkness—essentially corresponding to dawn and dusk. The software 'should allow an individual to get over jet lag in less than half the time than if one use other well-known recommendations,' says Daniel Forger of the University of Michigan, a co-author of the study. M. The schedules themselves haven't been tested in controlled environments; the data people submit will be used to test the efficacy of the recommendations in the real world—and the team says they have data from over 5,000 people so far. 'Hopefully our schedules can be integrated into more devices so that they become easier to follow,' says lead developer of Entrain, mathematician Olivia Walch at the University of Michigan. 'Maybe hotels could offer 10,000lux lights so that people can get bright daylight when they need it to push their clocks in the right direction.' N. You can start to fill in the new time zone by altering their habits of rest and and meals gradually. For example, you may sleep earlier and ensure the room where you sleep is totally dark and quiet. You can also eat a bit earlier or late and eat some snacks just to make your body adjust to the new rhythm. O. Though by far there is no solution to solve this problem completely, scientists said we can still adjust our bodies with those means mentioned above which can greatly lighten the unpleasant feeling caused by jet lag.

单选题It's 2:20 and he said he'd be here at 2:30. He ______ be here soon.

单选题He knew that the area"s rich plant life had been severely ______ by the huge herds of cows grazing the land.

单选题 The Price of Oil and the Price of Carbon A. Fossil fuel prices are likely to stay 'low for long.' Notwithstanding important recent progress in developing renewable fuel sources, low fossil fuel prices could discourage further innovation in, and adoption of, cleaner energy technologies. The result would be higher emissions of carbon dioxide and other greenhouse gases. B. Policymakers should not allow low energy prices to derail the clean energy transition. Action to restore appropriate price incentives, notably through corrective carbon pricing, is urgently needed to lower the risk of irreversible and potentially devastating effects of climate change. That approach also offers fiscal benefits. C. Oil prices have dropped by over 60% since June 2014. A commonly held view in the oil industry is that 'the best cure for low oil prices is low oil prices.' The reasoning behind this saying is that low oil prices discourage investment in new production capacity, eventually shifting the oil supply curve backward and bringing prices back up as existing oil fields—which can be tapped at relatively low marginal cost—are depleted. In fact, in line with past experience capital expenditure in the oil sector has dropped sharply in many producing countries, including the United States. The dynamic adjustment to low oil prices may, however, be different this time around. D. Oil prices are expected to remain lower for longer. The advent of new technologies has added about 4.2 million barrels per day to the crude oil market, contributing to a global over-supply. In addition, other factors are putting downward pressure on oil prices: change in the strategies behavior of the Organization of Petroleum Exporting Countries, the projected increase in Iranian exports, the scaling-down of global demand (especially from emerging markets), the long-term drop in petroleum consumption in the United States, and some displacement of oil by substitutes. These likely persistent forces, like the growth of shale(页岩) oil, point to a 'low for long' scenario. Futures markets, which show only a modest recovery of prices to around $60 a barrel by 2019, support this view. E. Natural gas and coal—also fossil fuels—have similarly seen price declines that look to be long-lived. Coal and natural gas are mainly used for electricity generation, whereas oil is used mostly to power transportation, yet the prices of all these energy sources are linked. The North American shale gas boom has resulted in record low prices there. The recent discovery of the giant Zohr gas field off the Egyptian coast will eventually have impact on pricing in the Mediterranean region and Europe, and there is significant development potential in many other places, notably Argentina. Coal prices also are low, owing to over-supply and the scaling-down of demand, especially from China, which burns half of the world's coal. F. Technological innovations have unleashed the power of renewables such as wind, hydro, solar, and geothermal (地热). Even Africa and the Middle East, home to economies that are heavily dependent on fossil fuel exports, have enormous potential to develop renewables. For example, the United Arab Emirates has endorsed an ambitious target to draw 24% of its primary energy consumption from renewable sources by 2021. G. Progress in the development of renewables could be fragile, however, if fossil fuel prices remain low for long. Renewables account for only a small share of global primary energy consumption, which is still dominated by fossil fuels—30% each for coal and oil, 25% for natural gas. But renewable energy will have to displace fossil fuels to a much greater extent in the future to avoid unacceptable climate risks. H. Unfortunately, the current low prices for oil, gas, and coal may provide little incentive for research to find even cheaper substitutes for those fuels. There is strong evidence that both innovation and adoption of cleaner technology are strongly encouraged by higher fossil fuel prices. The same is true for new technologies for alleviating fossil fuel emissions. I. The current low fossil fuel price environment will thus certainly delay the energy transition from fossil fuel to clean energy sources. Unless renewables become cheap enough that substantial carbon deposits are left underground for a very long time, if not forever, the planet will like be exposed to potentially catastrophic climate risks. J. Some climate impacts may already be discernible. For example, the United Nations Children Fund estimates that some 11 million children in Africa face hunger, disease, and water shortage as a result of the strongest El Niño(厄尔尼诺) weather phenomenon in decades. Many scientists believe that El Niño events, caused by warming in the Pacific, are becoming more intense as a result of climate change. K. Nations from around the world have gathered in Paris for the United Nations Climate Change Conference, COP 21, with the goal of a universal and potentially legally-binding agreement reducing greenhouse gas emissions. We need very broad participation to fully address global tragedy that results when countries fail to take into account the negative impact of their carbon emissions on the rest of the world. Moreover, non-participation by nations, if sufficiently widespread, can undermine the political will of participating countries to act. L. The nations participating at COP 21 are focusing on quantitative emissions-reduction commitments. Economic reasoning shows that the least expensive way for each country is to put a price on carbon emissions. The reason is that when carbon is priced, those emissions reductions that are least costly to implement will happen first. The International Monetary Fund calculates that countries can generate substantial fiscal revenues by eliminating fossil fuel subsidies and levying carbon charges that capture the domestic damage caused by emissions. A tax on upstream carbon sources is one easy way to put a price on carbon emissions, although some countries may wish to use other methods, such as emissions trading schemes. In order to maximize global welfare, every country's carbon pricing should reflect not only the purely domestic damage from emissions, but also the damage to foreign countries. M. Setting the right carbon price will therefore efficiently align the costs paid by carbon users with the true social opportunity cost of using carbon. By raising relative demand for clean energy sources, a carbon price would also help align the market return to clean-energy innovation with its social return, spurring the refinement of existing technologies and the development of new ones. And it would raise the demand for technologies such as carbon capture and storage, spurring their further development. If not corrected by the appropriate carbon price, low fossil fuel prices are not accurately signaling to markets the true social profitability of clean energy. While alternative estimates of the damage from carbon emissions differ, and it's especially hard to reckon the likely costs of possible catastrophic climate events, most estimates suggest substantial negative effects. N. Direct subsidies to research and development have been adopted by some governments but are a poor substitute for a carbon price; they do only part of the job, leaving in place market incentives to overuse fossil fuels and thereby add to the stock of atmospheric greenhouse gases without regard to the collateral (附带的) costs. O. The hope is that the success of COP 21 opens the door to future international agreement on carbon prices. Agreement on an international carbon-price floor would be a good starting point in that process. Failure to address comprehensively the problem of greenhouse gas emissions, however, exposes all generations, present and future, to incalculable risks.

单选题Only by shouting at the top of his voice _____.

单选题Niagara Falls is a great tourist _____drawing millions of visitors every year.

单选题He's far ______ of the others in mathematics.

单选题She ______ the words, not knowing what to say, how to put into plain speech her decision to finish their love.

单选题The change in the treatment of his characters is a significant ______ to Shakespeare's growth as a dramatist.

单选题We should concentrate on sharply reducing interest rates to pull the economy out of ______. A. rejection B. restriction C. retreat D. recession

单选题The reference to "Naiman and his colleagues (1978)" in paragraph 4 is made ______.