单选题______ be careful in making such experiments.

单选题Crocodiles (鳄鱼) lay their eggs and leave them under leaves or sand. Baby crocodiles have special sharp teeth with which to break their way out of the shells. Crocodiles only live where it is hot. They are found in India, Australia, Africa and America. They spend most of their time lying around in the mud or the rivers. The crocodile's long powerful tail is used when the animal is swimming. It is also an excellent weapon, because it can be swung with great speed and force. One blow will knock down a man or even a big animal at once. The crocodile is very well protected against its enemies by the hard bony plates which cover most of its body, but because of the way its neck is formed, it cannot turn its head from side to side and so it can only see in front of itself. The crocodile has its teeth cleaned by the crocodile bird. For its food this bird takes the bits left in the crocodile's mouth. This helps the crocodile, which cannot clean its own teeth, for it cannot move its tongue up and down. With its rows of terrible pointed teeth it seizes its food, which may be a fish, an animal, or even a careless human being, and then holds it below the water until it is drown to death. The long-nosed crocodile is shy and timid and because of this, the people of West Africa where it lives, sometimes catch it for food. Many, many centuries ago there were crocodiles in England. We know this because we have found their bones buried far down in the earth on which London is built. But the Britain of today is too" cold for them to live in. Crocodiles may grow to over thirty feet in length. When they lie floating in the water, they look like floating tree-trunks and it is often impossible to tell that they are there.

单选题Paul Samuelson revolutionized ______ by presenting his students with the most advanced economic thinking at an introductory level. 

单选题 If you want to set up a company, you must comply with the regulations laid down by the authorities.

单选题The sales manager was so Uadamant/U about her idea that it was out of the question for any one to talk her out of it.

单选题W:A man from AT&T would like to talk with the manager on the new project. Is she available?M:______

单选题此题为音频题

单选题There are many commonly held beliefs about eyeglasses and eyesight that are not proven facts. For instance, some people believe that wearing glasses too soon weakens the eyes. But there is no evidence to show that the structure of eyes is changed by wearing glasses at a young age. Wearing the wrong glasses, however, can prove harmful. Studies show that for adults there is no danger, but children can develop loss of vision if they have the wrong glasses. We have all heard some of the common myths about how eyesight gets bad. Most people believe that reading in dim light causes pool eyesight, but that is unique. Too little light makes the eyes work harder, so they do get tired and strained. Eyestrain also results from reading a lot, reading in bed, and watching too much television. But, although eyestrain may cause some pain or headaches, it does not permanently damage eyesight. Another myth about eyes is that they can be replaced, or transferred from one person to another. There are close to one million nerve fibers that connect the eyeball to the brain, and as if yet it is impossible to attach them all in a new person. Only certain parts of the eye—the cornea and the retina-can be replaced. But if we keep clearing up the myths and learning more about the eyes, someday a full transplant may be possible!

单选题______ the traffic jam, we would have caught our train.A. But forB. Because ofC. By means ofD. Due to

单选题We have arranged to go to the cinema on Friday, but we can be _____ and go another day.

单选题Every reader thinks that Jack is not ______ much a writer as a reporter.

单选题The modern age is a permissive one in which things can be said explicitly, but the old traditon of ______ dies hard.

单选题Laura was married for 6 months. Her husband was using drugs. She didn't want her son or her unborn baby to live that way, but she was afraid to ask her husband to leave. She left him a note instead. After reading the note, Laura's husband waited for her to come home and then beat her and her son. Laura had little education and she never had a good paying job. She was ashamed to ask for help from the police, courts or women's shelters. Sometimes her husband was very nice to her. She decided to try harder so her children could have a home and a father. Laura joined a church and told a priest about her problem. But her husband kept using drugs and hurting the family. Finally, she told her husband she loved him, but they should live apart for a while. He beat her again. The priest came over to talk to her. He asked the husband to go out for a while. Laura packed up her things and left home with her son. The next day she lost the baby. Her husband went to jail. Laura got a lot of help from groups that help women who have been beaten. Now she is in college, has her own apartment and works on special projects at a women's shelter. "We got out, and it changed life for me and my child. You can do it. You can break the cycle," Laura said.

单选题Lightning has been the second largest storm killer in the US over the past 40 years and is ______ only by flood. A. exceeded B. excelled C. excluded D. extended

单选题What is the advertised job?

单选题This is Mr Brown, _____I think has exciting news to tell you.

单选题It is ______ understood by all concerned that the word no one who visits him ever breathe a syllable of in his hearing will remain forever unspoken.

单选题 On a clear, cold day in early March 2019, Justin Jordan, a fifth-generation grower in Lacona, Iowa, reads attentively old maps spread across his dining-room table. One creased, yellowing chart shows a soil-conservation plan his grandfather created with the USDA (United States Department of Agriculture) in the 1950s, including terraces for controlling erosion and areas designated for tree planting. The agency was working to reverse critical topsoil loss from decades of mass-scale plowing. His grandfather implemented part of the scheme. But new synthetic fertilizers, which could boost yields by 50 percent, made the situation less terrible, so he continued cultivating their corn and soybean fields each year. As did Jordan's dad, and most other farmers. Over the past 150 years, cultivation has chewed up about half of Earth's topsoil. Jordan, an polite, soft-spoken man in his late 30s, stopped plowing and began planting cover crops when he took over in the early 2000s. 'I was eager to do things in a different way,' he says. 'It just seemed like every year the topsoil was getting thinner.' Jordan tends 410 acres—larger than most farms selling vegetables at Saturday markets, but tiny compared with 10,000-acre corporate operations. Aerial photos show the contrast between his land and that of other farmers, most of whom continue deep cultivation. His soil is dark and rich, but from the air, his fields appear lighter, covered in accumulated mulch (胡根物). Strips of hay grass (for his cattle) and native prairie species cover across the slopes—year-round plants that pump carbon into the soil. Neighboring barren fields steadily release it. Once Jordan brings in his corn in October, he sows a cover of rye (黑麦) among the drying stalks that stays green through the following spring, when he cuts it down and seeds next year's crop in the mulch. He sprinkles his soybean fields before the September harvest with a cocktail of rye, radishes, and oats, creating a mini forest beneath the knee-high cash crop. With all these changes, his yields have remained roughly the same as his neighbors'. Soon, folks like Jordan might gain a financial edge. The Terraton Initiative, the nation's first carbon market dedicated to agriculture, launched in June 2019 out of the farm-tech startup Indigo Ag. Companies that want to offset their emissions purchase credits; Terraton then pays growers $15 per ton for the carbon their land captures. Within six months, farmers tending a total of 10 million acres worldwide expressed interest in signing up. More cash would be nice, but climate change is the motivating factor for Jordan—out of global concern, and to keep his harvest from washing away.

单选题The picture is______, please straighten it.

单选题I'm going to the hairdresser's to ______.