单选题A peculiarly pointed chin is his most memorable facial characteristic .

单选题Not everybody has the competence to do this job.A. competitionB. comparisonC. controlD. ability

单选题While we don"t agree, we continue to be friends.

单选题Gunpowder was used extensively in firearms prior to 1990.A. inB. aroundC. fromD. before

单选题Smart Window Windows not only let light in to cut down an electricity use for lighting, but the light coming through the window also provides heat. However, windows are not something people typically associate with being a cutting edge technology. Researchers are now working on new technologies that enable a window to quickly change from clear to dark and anywhere in between with a flip of a switch. "It took us a long time to figure out what a window really is," says Claes Granqvist. He"s a professor of solid-state physics at Uppsala University in Sweden. "It"s contact with the outside world. You have to have visual contact with the surrounding world to feel well." So, windows and natural light are important for improving the way people feel when they"re stuck indoors. Yet, windows are the weak link in a building when it comes to energy and temperature control. In the winter, cold air leaks in. When it"s hot and sunny, sunlight streams in. All of this sunlight carries lots of heat and energy. And all of this extra heat forces people to turn on their air conditioners. Producing blasts of cold air, which can feel so refreshing, actually suck up enormous amounts of electricity in buildings around the world. Windows have been a major focus of energy research for a long time. Over the years, scientists have come up with a variety of strategies for coating, glazing, and layering windows to make them more energy efficient. Smart windows go a step further. They use chromogenic technologies which involve changes of color. Electrochromic windows use electricity to change color. For example, a sheet of glass coated with thin layers of chemical compound such as tungsten oxide works a bit like a battery. Tungsten oxide is clear when an electric charge is applied and dark when the charge is removed, that is, when the amount of voltage is decreased, the window darkens until it"s completely dark after all electricity is taken away. So applying a voltage determines whether the window looks clear or dark. One important feature that makes a smart window so smart is that it has a sort of "memory." All it takes is a small jolt of voltage to turn the window from one state to the other. Then, it stays that way. Transitions take anywhere from 10 seconds to a few minutes, depending on the size of the window. The development of smart windows could mean that massive air conditioning systems may no longer need. "In the future," Granqvist says, "our buildings may look different."

单选题Gardner thinks that his theory has a ________ .

单选题The Klondike was the scene of one of the biggest gold rushes the world has ever known.

单选题The council meeting terminated at 2 o"clock.

单选题It was amazing that the boy was able to solve the problem so quickly. A. frustrating B. unexpected C. reasonable D. surprising

单选题Relief workers were shocked by what they saw.

单选题The current external surplus declined {{U}}further{{/U}}.

单选题At midnight, we were Uaroused/U by a knock at the door.

单选题Skin Cancer Melanoma (黑素瘤), the deadliest kind of skin cancer, is now the most common cancer in (51) British women, the country's leading cancer organization said Wednesday. Skin cancer has (52) cervical (子宫颈的) cancer as the top cancer striking women in their 20s, according to the latest data from Cancer Research United Kingdom. The trend is particularly (53) since younger people are not generally those most susceptible (易患的) to melanoma. Rates of skin cancer are (54) highest in people over age 75. But experts worry that increasing numbers of younger people being diagnosed with skin cancer could be the (55) of a dangerous trend. Women in their 20s make (56) a small percentage of all patients diagnosed with melanoma in Britain, but nearly a third of all cases occur in people younger than 50. Based on current numbers, Cancer Research UK predicts that melanoma will become the fourth (57) common cancer for men and women of all ages by 2024, and that cases will jump from about 9,000 cases a year to more than 15,500. Cancer experts (58) the rising number of skin cancer cases largely to the surge in people using tanning salons. "Spending time on sun beds is just as (59) as staying out too long in the sun," said Caroline Cerny of Cancer Research UK. The organization is starting a SunSmart (60) to warn Britons of the dangers of being too bronzed. "The intensity of ultraviolet rays in some sun beds can be more than 10 (61) stronger than the midday sun," Cerny said. In the United States, several states require parental approval (62) minors can use tanning salons. Wisconsin bans people 16 and (63) from using tanning beds, and others ban children under 14. At least 29 states have regulations governing minors' use of tanning salons. In the U. K. , Scottish politicians passed legislation banning those under 18 from using tanning beds, though it hasn't yet been implemented. There are no plans for (64) in the rest of the U. K. The World Health Organization has previously recommended that tanning beds be regulated because of their potential to damage DNA in the skin. Experts said most deadly skin cancers could be (65) if people took the proper precautions when in the sun and avoided tanning beds.

单选题This kind of animal became {{U}}extinct{{/U}} about 500 years ago.

单选题In Britain and many other countries, {{U}}appraisal{{/U}} is now a tool of management. A. evaluation B. production C. efficiency D. publicity

单选题His kidney was given to his daughter so as to save her life.A. transformedB. transportedC. transmittedD. transplanted

单选题Please {{U}}ensure{{/U}} that your seatbelts are fastened while driving.

单选题By investing wisely she accumulated a fortune.

单选题The police managed to {{U}}track down{{/U}} the man in New York.

单选题Enamel,the hardest substance in a human being's body,covers the entire crown of the tooth.