单选题if headaches only Uoccur/U at night, lack of fresh air is often the cause.

单选题Grounded whales often struggle fruitlessly to reenter deep water.

单选题About eight million school-age children are home alone after school. These are the hours when the number of violent crimes peaks and when youths are most likely to experiment with alcohol, tobacco, and drugs. Many older children take care of themselves after school for an hour or two until a parent comes home, and research suggests that some of these children are more at risk of poor grades and risky behaviors. Studies have been done to find out what helps to reduce these kinds of risky behaviors among youths. One study of Chicago neighborhoods showed that after-school programs resulted in less violence even in poor neighborhoods. After-school programs can help to reduce crime and violence because they offer activities to children and youths during their out-of-school time. In addition to helping youths make use of after-school hours, after-school programs provide teens with opportunities to develop caring relationships with adults. Studies have found that high-quality relationships with parents and other adults, as well as good use of time, are very important for healthy development in youth. After-school programs can also be used for teens who hang out at friends" houses and play basketball when a parent or other responsible adult is at home. The programs can also be helpful for formal after-school activities, including "drop-in" programs that are provided by organizations. Despite the benefits of after-school programs, there are many reasons why some parents do not use them. Programs may be too expensive, of poor quality, or hard to join. Some older children and young teens may refuse to attend programs that seem like they are just child care. Parents may feel uncertain about how much freedom is proper for children and youths who are beyond the traditional child care years. However, research supports the effectiveness of these programs in protecting middle school and high school youths from risk and harm.

单选题The fact that he has been quite frank in admitting his mistakes Ucounts/U a lot to his credit.

单选题They agreed to modify their policy.

单选题Eleanor Roosevelt's dedication to humanitarian causes won her affection and honor at home and abroad.A. on the airB. henceforthC. nearbyD. in foreign countries

单选题He told the police that he had thought honestly about the Uethics/U of what he was doing.

单选题下面有3篇短文，每篇短文后有5道题，每题后面有4个选项。请仔细阅读短文并根据短文回答其后面的问题，从4个选项中选择1个最佳答案。{{B}}第一篇{{/B}} {{B}}A New Finding{{/B}} British cancer researchers have found that childhood leukaemia is caused by an infection and clusters of cases around industrial sites are the result of population mixing that increases exposure. The research published in the British Journal of Cancer backs up a 1988 theory that some as yet unidentified infection caused leukaemia—not the environmental factors widely blamed for the disease. “Childhood leukaemia appears to be an unusual result of a common infection,” said Sir Richard Doll, an internationally—known cancer expert who first linked tobacco with lung cancer in 1950. “A virus is the most likely explanation. You would get an increased risk of it if you suddenly put a lot of people from large towns in a rural area, where you might have people who had not been exposed to the infection.” Doll was commenting on the new findings by researchers at Newcastle University, which focused on a cluster of leukaemia cases around the Sellafield nuclear reprocessing plant in Cumbria in northern England. Scientists have been trying to establish why there was more leukaemia in children around the Sellafield area, but have failed to establish a link with radiation or pollution. The Newcastle University research by Heather Dickinson and Louise Parker showed the cluster of cases could have been predicted because of the amount of population mixing going on in the area, as large numbers of construction workers and nuclear staff moved into a rural setting. “Our study shows that population mixing can account for the (Sellafield) leukaemia cluster and that all children, whether their parents are incomers or locals, are at a higher risk if they are born in an area of high population mixing,” Dickinson said in a statement issued by the Cancer Research Campaign, which publishes the British Journal of Cancer. Their paper adds crucial weight to the 1988 theory put forward by Leo Kinlen, a cancer epidemiologist at Oxford University, who said that exposure to a common unidentified infection through population mixing resulted in the disease.

单选题Crayfish, small freshwater crustacean similar to lobsters, are {{U}}consumed{{/U}} by inhabitants of the Mississippi River Basin.

单选题My sister has a Utalent/U for music.

单选题A long journey in cold weather is dreadfully tiring.

单选题She has such Uexceptional/U abilities that everyone is jealous of her.

单选题The cars {{U}}traveled{{/U}} 200 miles a day.

单选题Michael is now merely a good friend.

单选题A deadly disease has affected these animals.A. contagiousB. seriousC. fatalD. worrying

单选题It's hard for us to {{U}}choose{{/U}} a book among these books. A. elect B. buy C. recognize D. select

单选题The last few weeks have been enjoyable.

单选题That guy is really {{U}}witty{{/U}}. A. ugly B. smart C. honorable D. popular

单选题She was the one in the whole class who was eligible to apply for the scholarship.

单选题Which of the following statements is NOT true of the weather in England?