完形填空. Cell Phone Lets Your Secret out Your cell phone holds secrets about you. Besides the names and 1 that you've programmed into it, traces of your DNA linger on the device, according to a new study. DNA is genetic material that 2 in every cell. Like your fingerprint, your DNA is unique to you— 3 you have an identical twin. Scientists today routinely analyze DNA in blood, saliva, or hair left 4 at the scene of a crime. The results often help detectives identify 5 and their victims. Your cell phone can reveal more about you 6 you might think. Meghan J. McFadden, a scientist at McMaster University in Hamilton, Ontario, heard about a crime in which the suspect bled onto a cell phone and later dropped the 7 . This made her wonder whether traces of DNA lingered on cell phones—even when no blood was involved. 8 she and her colleague Margaret Wallace of the City University of New York analyzed the flip-open phones of 10 volunteers. They used swabs to collect 9 traces of the users from two parts of the phone: the outside, where the user holds it, and the 10 , which is placed at the user's ear. The scientists scrubbed the phones using a solution made mostly 11 alcohol. The aim of washing was to remove all detectable traces of DNA. The owners got their phones 12 for another week. Then the researchers collected the phones and repeated the swabbing of each phone once more. The scientists discovered DNA that 13 to the phone's speaker on each of the phones. Better samples were collected from the outside of each phone, but those swabs also picked up DNA that belonged to other people who had apparently also handled the phone. 14 , DNA showed up even in swabs that were taken immediately after the phones were scrubbed. That suggests that washing won't remove all traces of evidence from a criminal's device. So cell phones can now be added to the 15 of clues that can clinch a crime-scene investigation.1.

完形填空. A Biological Clock Every living thing has what scientists call a biological clock that controls behavior. The biological clock tells 1 when to form flowers and when the flowers should open. It tells 2 when to leave the protective cocoons and fly away, and it tells animals and human beings when to eat, sleep and wake. Events outside the plant and animal 3 the actions of some biological clocks. Scientists recently found, for example, that a tiny animal changes the color of its fur 4 the number of hours of daylight. In the short 5 of winter, its fur becomes white. The fur becomes gray brown in color in the longer hours of daylight in summer. Inner signals control other biological clocks. German scientists found that some kind of internal clock seems to order birds to begin their long migration 6 twice each year. Birds 7 flying become restless when it is time for the trip, 8 they become calm again when the time of the flight has ended. Scientists say they are beginning to learn which 9 of the brain contain biological clocks. An American researcher, Martin Moorhead, said a small group of ceils near the front of the brain 10 to control the timing of some of our actions. These 11 tell a person when to 12 , when to sleep and when to seek food. Scientists say there probably are other biological clock cells that control other body activities. Dr. Moorhead is studying 13 our biological clocks affect the way we do our work. For example, most of us have great difficulty if we must often change to different work hours. 14 can take many days for a human body to accept the major change in work hours. Dr. Moorhead said industrial officials should have a better understanding of biological clocks and how they affect workers. He said 15 understanding could cut sickness and accidents at work and would help increase a factory's production.1.

填空题Ebola Outbreak 1 You are likely aware that sever

填空题Global Warming 1

填空题I'll Be Bach 1 Composer David Cope is the invento

填空题Optimists Really Do Live Longer

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补全短文A Major Composer Ludwig van Beethoven

单选题I wish Bob would drive us to the airport but he has __ to take us all.

单选题Now a person works for a certain amount of money _____ he can pay for food and clothing.

单选题The more he encouraged the boy, __

单选题I am unable to __ what he is saying.

单选题Some of the world’s best mountain scenery __ available near the Southern Alps.

单选题About nine men in every hundred 61 from color blindness in some way; women are luckier—only about one in two hundred is affected in this manner. Perhaps, after all, it is safer to be driven by a woman. There are different forms of color blindness. In some cases, a man may not be able to see deep red. He may think that red, orange and yellow are shades of green. Sometimes a person cannot 62 the difference between blue and green. In 63 cases, an unlucky man may see everything in shades of green--a 64 world indeed. Sometimes color blindness can be dangerous. For example, when in the forest 65 soldiers use 66 to signal to 67. A green light may mean" 68 "and a 69 light may mean "Danger, keep back." You can seen what will 70 if somebody thinks that is green.

单选题The bees __ out of their hive.

单选题He felt a bit ___ because her life seemed completely out of balance.

单选题When pessimists __ in their first attempt, they usually say, "I can't do this."

单选题I will leave him a note __ he will know where we are.

单选题The man __ that most poets and scientists are male.

单选题If things are going badly, the optimist acts quickly, looking for __ and forming a new plan of action.