单选题It is widely accepted that young babies learn to do things because certain acts lead to rewards .

单选题Evidence exists that hearing problems may be alleviated by changes in diet and exercise habits.

单选题The representative was asked to verify his earlier statement.A. confirmB. withdrawC. repeatD. modify

单选题Red giant stars do not become white dwarf stars abruptly; the process takes more than fifteen hundred years. A．suddenly B．in unison C．prematurely D．accidentally

单选题John is crazy about pop music.

单选题The benefits are {{U}}immense{{/U}}. A. immediate B. great C. equal D. moderate

单选题Since ancient times people have found various ways to preserve meat.

单选题Her faith upheld her in times of sadness.

单选题Age is one of the {{U}}variables{{/U}} which seems to determine the attitude of an older person toward conformity.

单选题The oldest preserved manuscripts are those written on papyrus, which were found in Egyptian tombs. A．protected B．hidden C．sought D．discovered

单选题Nerve signals may travel through nerve or muscle fibers at speeds as high as two hundred miles per hour. A．rates B．impacts C．ratios D．pulses

单选题Participation in intramural sports is required. A．within the school B．with outsiders C．overly strenuous D．extraordinary

单选题U.S. to Start $3.2 Billion Child Health Study in January 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 up 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 Scheid 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After years of research,Charles Drew devised a procedure for preserving plasma.

单选题According to Paragraph 2, many people start small businesses in order to

单选题Many forms of cancer can be cured if detected early

单选题The committee comprises five persons.A. absorbsB. concernsC. excludesD. involves

单选题I enjoyed the play-it had a clever plot and very funny dialogues.

单选题The plane will be taking off in approximately 10 minutes. A. about B. possibly C. probably D. rarely

单选题The Street Violinist I got up and dressed, stuck my violin under my jacket, and went out into the streets to try my luck. I wandered about for an hour, looking for a likely spot, feeling as though I were about to commit a crime. Then I stopped at last under a bridge near the station and decided to have a try. I felt tense and nervous. It was the first time, after all. I drew the violin from under my coat like a gun. It was here, in Southampton, with trains rattling overhead, that I was about to declare myself. One morning I was part of the hurrying crowds, the next I stood apart, my back to the wall, my hat on the pavement before me, the violin under my chin. The fist notes I played were loud and raw, like a declaration of protest. Then they settled down and began to run more smoothly and to stay more or less in turn. To my surprise I was neither arrested nor told to shut up. Indeed, nobody took any notice at all. Then an old man, without stopping, surreptitiously tossed a penny into my hat as though getting out of some guilty evidence. I worked the streets of Southampton for several days, gradually acquiring the truths of the trade by trial and error. It was not a good thing, for instance, to let the hat fill up with money—the sight could discourage the patron. Nor was it wise to empty it completely, which could also confuse him, giving him no hint as to where to drop his money. Placing a couple of pennies in the hat to start the thing going soon became a regular ritual, making sure between tunes, to hide most of the earnings, but always leaving two pennies behind. Old ladies were most generous, and so were women with children, shopgirls, typists and barmaids. As for the man, heavy drinkers were always willing listeners and so were big guys with muscles. But never a man with a gentleman's hat, briefcase or dog. Respectable types were the meanest of all. Except for retired army officers, who would tell " why aren't you working, young man?" and then toss some money into the hat to hide their confusion.