单选题Tom"s wife succeeded in persuading him into giving up smoking.

单选题Smoking Can Increase Depressive Symptoms in Teens While some teenagers may use cigarettes to "self-medicate" (自我治疗) against the blues (忧郁), scientists at the University of Toronto and the University of Montreal have found that smoking may actually (51) depressive symptoms in some teens. "This observational study is one of the few to examine the perceived (52) benefits of smoking among teens, "says lead researcher Michael Chaiton, a research associate at the Ontario Tobacco Research Unit of the University of Toronto. " (53) cigarettes may appear to have self-medicating effects or to improve mood, in the long (54) we found that teens who started to smoke reported higher depressive symptoms. " As part of the study, some 662 high school teenagers completed up to 20 questionnaires about their use of cigarettes to (55) mood. Secondary schools were selected to provide a mix of French and English participants, urban and rural schools, and schools (56) in high, moderate and low socioeconomic neighbourhoods. Participants were divided into three (57) : never smokers; smokers who did not use cigarettes to self-medicate, improve mood or physical (58) : smokers who used cigarettes to self-medicate. Depressive symptoms were measured using a scale that asked how often participants felt too tired to do things; had (59) going to sleep or staying asleep; felt unhappy, sad, or depressed; felt hopeless about the future; felt anxious or tense; and worried too much about things. "Smokers who used cigarettes as mood (60) had higher risks of elevated (提升) depressive symptoms (61) teens who had never smoked, " says co-researcher Jennifer O'Loughlin, a professor at the University of Montreal Department of Social and Preventive Medicine. "Our study found that teen smokers who reported emotional benefits from smoking are (62) higher risk of developing depressive symptoms. "The (63) between depression and smoking exists (64) among teens that use cigarettes to feel better. "It's (65) to emphasize that depressive symptom scores were higher among teenagers who reported emotional benefits from smoking after they began to smoke, "says Dr. Chaiton.

单选题Cement was seldom used in buildings of the Middle Ages.

单选题Hersheypark began Uintegrating/U recycling into its public information programs more than five years ago.

单选题I realized to my {{U}}horror{{/U}} that I had forgotten the present.

单选题Young Adults Who Exercise Get Higher IQ Scores Young adults who are fit have a higher IQ and are more likely to go on to university, reveals a major new study 1 out at the Sahlgrenska Academy and Sahlgrenska University Hospital. The results were recently published in the Proceedings of the National Academy of Sciences (PNAS). The study 2 1.2 million Swedish men doing military service who were born between 1950 and 1976. The research group analyzed the 3 of both physical and IQ tests the youngsters took right after they started serving the army. The study shows a clear link 4 good physical fitness and better results for the IQ test. The strongest links are for 5 thinking and verbal comprehension. But it is only fitness that plays a 6 in the results for the IQ test, and not strength. "Being fit means that you also have good heart and lung 7 and that your brain gets plenty of oxygen," says Michael Nilsson, professor at the Sahlgrenska Academy and chief physician at the Sahlgrenska University Hospital. "This may be one of the reasons why we can see a clear link with fitness, but not with muscular 8 . We are also seeing that there are growth factors that are important." By analyzing data for twins, the researchers have been 9 to determine that it is primarily environmental factors and not genes that 10 the link between fitness and a higher IQ. "We have also shown that those youngsters who 11 their physical fitness between the ages of 15 and 18 increase their performance," says Mafia berg, researcher at the Sahlgrenska Academy and physician at a health centre. "This being the case, physical education is a 12 that has an important place in schools, and is an absolute must 13 we want to do well in math and other theoretical subjects." The researchers have also compared the results from fitness tests during national service 14 the socioeconomic status of the men later in life. Those who were fit at 18 were more 15 to go into higher education, and many secured more qualified jobs.

单选题Tom"s wife succeeded in persuading him into giving up smoking.

单选题UApart from/U one or two minor mistakes, I thought the concert was excellent.

单选题People have to change their jobs from time to time.

单选题The word "vandalizing" in Line 17 means

单选题She is a highly successful teacher.

单选题The caliber of F. Scott Fitzgerald"s writing was reassessed by literary critics in the 1950"s.

单选题These are their{{U}} motives{{/U}} for doing it-

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

单选题Accidents caused by car doors being opened into the path of oncoming vehicles or cyclists are common in cities. But these incidents could become a thing of the past, if doors that react to potential impacts catch on. …… The current prototype looks like a normal ear door, but an extra metal bar runs through its centre and connects to the ear's flame between the hinges. In normal mode, the bar moves freely and doesn't affect the door's movement. However, if sensors detect a nearby obstacle at the same time as an accelerometer (加速度讲; 加速仪) detects an attempt to open the door, the door's swing is restricted by a linear motor attached to the bar. The design of the intelligent door is designed in such a way that the door becomes hard to open whenA. there is an obstacle nearby.B. there is something wrong with the accelerometer.C. there is something wrong with the sensors.D. there is an accelerometer in the car.

单选题There should be laws that prohibit smoking around children. A. forbid B. advocate C. inherit D. withdraw

单选题"Life Form Found" on Saturn's Titan Scientists say they have discovered hints of alien life on the Saturn's moon. The discovery of a sort of life was announced after researchers at the US space agency, NASA, analyzed data from spacecraft Cassini, which pointed to the existence of methane-based form of life on Saturn's biggest moon. Scientists have reportedly discovered clues showing primitive alien beings are "breathing" in Titan's dense atmosphere filled with hydrogen. They argue that hydrogen gets absorbed before hitting Titan's planet-like surface covered with methane lakes and rivers. This, they say, points to the existence of some "bugs" consuming the hydrogen at the surface of the moon less than half the size of the Earth. "We suggested hydrogen consumption because it's the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth," says NASA scientist Chris McKay. "If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth. " To date, scientists have not yet detected this form of life anywhere, though there are liq-uid-water-based microorganisms on Earth that grow well on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin (minus 290 degrees Farenheit), a methane-based organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan's surface and much too cold to support life as we know it. Scientists had expected the Sun's interactions with chemicals in the atmosphere to produce a coating of acetylene on Titan's surface. But Cassini detected no acetylene on the surface. The absence of detectable acetylene on the Titan's surface can very well have a non-bio-logical explanation, said Mark Allen, a principal investigator of the NASA Titan team. "Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed," Alien said. "We have a lot of work to do to rule out possible non-biological explanations. It is more likely that a chemical process, without biology, can explain these results. /

单选题Since about 1970, new research has helped brain scientists understands these problems better. Scientists now know there are many different kinds of learning disabilities and that they are caused by many different things. There is no longer any question that all learning disabilities result from differences in the way the brain is organized. You can' t look at a child and tell if he or she has a learning disability. There is no outward sign of the disorder. So some researchers began looking at the brain itself to learn what might be wrong. In one study, researchers examined the brain of a learning disabled person who had died in an accident. They found two unusual things. One involved cells in the left side of the brain, which control language. These cells normally are white. In the learning disabled person, however, these ceils were gray. The researchers also found that many of the nerve ceils were not in a line the way they should have been. The nerve cells were mixed together. The study was carried out under the guidance of Norman Geschwind, an early expert on learning disabilities. Doctor Geschwind proposed that learning disabilities mainly resultes from problems in the left side of the brain. He believed this side of the brain failed to develop normally. Probably, he said, nerve cells there didn't connect as they should. So the brain was like an electrical device in which the wires were crossed. Other researchers didn't examine brain tissue. Instead, they measured the brain's electrical activity and made a map of the electrical signals. Frank Dully experimented with this technique at Children's Hospital Medical Center in Boston. Dr. Duffy found large differences in the brain activity of normal children and those with reading problems. The differences appeared throughout the brain. Dr. Dully said his research is evidence that reading disabilities involve damage to a wide area of the brain, not just the left side.

单选题The nursery is bright and cheerful .

单选题The child"s abnormal behavior puzzled the doctor.