单选题They converted the spare bedroom into an office.

单选题That is a problem really beyond my grasp.A. concentrationB. comprehensionC. complimentD. compromise

单选题You have to be patient if you want to {{U}}sustain{{/U}} your position. A. maintain B. establish C. acquire D. support

单选题The mountains look glorious at sunrise.

单选题Florida Hit by Cold Air Mass In January, 2003, the eastern two-thirds of the United States was at the mercy of a bitterly cold air mass that has endangered Florida"s citrus trees, choked northern harbors with ice and left bewildered residents of North Carolina"s Outer Bands digging out of up to a foot of snow. The ice chill deepened as temperatures fell to the single digits in most of the South, with an unfamiliar dip below the freezing mark as far south as parts of interior South Florida. Temperatures in Florida plunged, with West Palm Beach dropping to a record low of 2 degrees. "We couldn"t believe how cold it was," said Martin King, who arrived this week in Orlando from England. "We brought shorts, T-shirt, and I had to go out and buy another coat." The temperature plunge posed a threat to Florida"s USD-9.1-billion-a-year citrus crop, more of which is still on the trees. Growers were hurrying to harvest as much of the fruit as possible before it was damaged by cold. "Time is of the essence in getting fruit to the plant," said Tom Rogers, a citrus grower who expected to see damage to oranges and grapefruit at that time. In Florida, Governor Jeb Bush signed an emergency order to eliminate the weight limit on trucks so citrus growers could get as much fruit to market as possible. Casey Pace, a spokeswoman for Florida Citrus Mutual, said growers had sprayed trees with sprinklers, which created a layer of ice and helped maintain a temperature near freezing. Citrus trees are considered in danger of damage if the temperature drops below minus 2 degrees Celsius for four hours or more. Snow ranging from a dusting to up to 30 centimeters blanketed the Carolinas, Tennessee and parts of Virginia.

单选题The idea of using HIV for a beneficial purpose has been widely accepted.

单选题There are a limited number of books on this subject in the library.

单选题Cell Phones:Hang Up or Keep Talking? Millions of people are using cell phones today. In many places it is actually considered unusual not to use one. In many countries, cell phones are very popular with young people. They find that the phones are more than a means of communication--having a mobile phone shows that they are cool and connected. The explosions around the world in mobile phone use make some health professionals worried. Some doctors are concerned that in the future many people may suffer health problems from the use of mobile phones. In England. there has been a serious debate about this issue. Mobile phone companies are worried about the negative publicity of such ideas. They say that there is no proof that mobile phones are bad for your health. On the other hand,why do some medical studies show changes in the brain cells of some people who use mobile phones? Signs of change in the tissues of the brain and head can be detected with modern scanning(扫描)equipment. In one case, a traveling salesman had to retire at a young age because of serious memory loss. He couldn't remember even simple tasks. He would often forget the name of his own son. This man used to talk on his mobile phone for about six hours a day,every day of his working week,for a couple of years. His family doctor blamed his mobile phone use, but his employer's doctor didn't agree. What is it that makes mobile phones potentially harmful? The answer is radiation. High-techma-chines can detect very small amounts of radiation from mobile phones. Mobile phone companies agree that there is some radiation, but they say the amount is too small to worry about. As the discussion about their safety continues,it appears that it's best to use mobile phones less often. Use your regular phone if you want to talk for a long time. Use your mobile phone only when you really need it. Mobile phones can be very useful and convenient, especially in emergencies. In the future, mobile phones may have a warning label that says they are bad for your health. So for now,it's wise not to use your mobile phone too often.

单选题Pregnancy Anomalies May Lower Breast Cancer Risk Certain abnormalities occurring in problem pregnancies are associated with a long-term reduction in risk of breast cancer, according to a study released on Tuesday that tracked women for four decades. Researchers led by epidemiologist Barbara Cohn of the Public Health Institute in Berkeley, California, examined records on 3,804 white women in the San Francisco area who were pregnant during the period from June 1959 through April 1967. The study found that three anomalies — two relating to the placenta and one involving the women's blood pressure — were linked with a big decline in breast cancer occurrence. Cohn said changes in the levels of hormones and other substances in the body caused by the abnormalities may produce a protective effect. She also noted that most of the women who experienced the anomalies still gave birth to healthy babies. "It's more subtle than to say what's bad for the baby is good for the mother. It's really not quite like that. " Cohn said in a telephone interview. She said she was hopeful that researchers could nail down the exact mechanisms at work in providing the long-term cancer protection for the women who experienced these complications. "It's certainly possible that one might be able to design a treatment or possibly a prevention that is related to these factors. " Cohn said. She said scientists have known for many years that events that occur in pregnancy have an impact on the risk of breast cancer. Cohn said her study provides new details about some specific characteristics of pregnancies that may relate to long-term protection against breast cancer. A. blood pressure increase experienced by the mother between the second and third trimesters of the pregnancy was associated with lower breast cancer incidence, the study found. Women whose increase was in the highest 25 percent of population studied had a 51 percent reduction in breast cancer rate. Women with a smaller placenta size ( weight and diameter) also had lower breast cancer rates. The placenta, the tissue that connects the mother and fetus, produces hormones to help maintain the pregnancy and allows the exchange of oxygen, nutrients and waste materials. In addition, women who experienced a condition known as maternal floor infarction of the placenta — a serious abnormality that can block the flow of oxygen and nutrients to the fetus — had a 60 percent reduction in breast cancer rate. All three risk factors in combination were linked with up to a 94 percent reduction in breast cancer incidence, the study concluded.

单选题The study also notes aU steady/U decline in the number of college students taking science courses．

单选题The company recommended that a new petrol station be built here.

单选题Prisoners were kept in the most {{U}}appalling{{/U}} conditions. A. flexible B. reasonable C. terrible D. serious

单选题I was astonished at the news of his escape.

单选题The President made a brief visit to Beijing.

单选题Talks on climate change resumed in the German city of Bonn on July 16 to combat global warming. A. focus on B. settle down C. fight against D. sum up

单选题Written records seldom tell social scientists all that they want to know about past cultures.

单选题During the past ten years there have been dramatic changes in the international situation.

单选题The document was compiled by the Department of Health.

单选题{{B}}第三篇{{/B}} {{B}}U.S. to Start $3.2 Billion Child Health Study in January{{/B}} A study that will cost $3.2 billion and last more than two decades to track the health of 100,000 U. S. children from before birth to age 21 will be launched in January, U. S. health officials said on Friday. Officials from the U.S. government's National Institutes of Health said they hope the study, to be conducted at 105 locations throughout the United States, can help identify early-life influences that affect later development, with the goal of learning new ways to treat or prevent illness. The study will examine hereditary and environmental factors such as exposure to certain chemicals that affect health. Researchers will collect genetic and biological samples from people in the study as well as samples from the homes of the women and their babies including air, water, dust and materials used to construct their residences, the NIH said. Officials said more than $200 million has been spent already and the study is projected to cost $3.2 billion. "We anticipate that in the long term, what we learn from the study will result in a significant savings in the nation's health care costs," Dr. Duane Alexander, who heads the NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development, told reporters. The study will begin in January when the University of North Carolina and the Mount Sinai School of Medicine in New York start signing up2 pregnant women whose babies will then be followed to age 21. Some of the early findings will be about factors behind pre-term birth, which has become more common in recent years, according to Dr. Peter Scheidt of the NIH, who heads the study. The people taking part will be from rural, urban and suburban areas, from all income and educational levels and from all racial groups, the NIH said.

单选题Structurally,the inside of early Christian churches was simple.