题目内容
One reason that we haven’t had his letter is that he it to our old address by mistake.
A. might send B. should have sent
C. should send D. may have sent
D
The bar-tailed godwit (斑尾鷸)has just broken its own record for the world’s longest non-stop flight, including humans in planes, according to a report made by Lund University Press. The bird can fly non-stop for eight days, while the most impressive man-made airplane can only remain in the sky for 82 hours without a stop.
The bar-tailed godwit’s journey, from Alaska to New Zealand, covers over 6,835 miles. It completes this trip twice a year, in autumn going to New Zealand, and in spring back to Alaska. The tireless bird ends the trip without stopping once for food or rest. All other birds can only finish trips that are twice as short as what the bar-tailed godwit travels.
One reason for the bar-tailed godwit’s success is that it has made the best use of its fuel, which is only 0.41 percent of its body weight over each hour of any given long flight. Hedenstrom, a professor from Lund University, says, “This figure is extremely low compared with other birds.” The bird also has a special body shape that helps it fly easily. It stores body fat and protein to manage its trips. It also travels fast, compared to other birds and animals.
Many questions remain about this bird record holder that never gets lost in the air. Researchers wonder whether it has an inside compass (指南针) that helps it to know the direction. Please watch how beautiful bar-tailed godwits look as they come in for a landing, along with other birds.
1.For the flight from Alaska to New Zealand, the bar-tailed godwit__________
A.doesn’t need to stop to eat |
B.is afraid of hot weather |
C.seems very tired at last |
D.should fly less than 7,000 meters |
2.The main reason why the bar-tailed godwit can break the record is that it ______.
A.eats little food every hour |
B.has a special body shape |
C.stores much water in its body |
D.has very light body weight |
3.The last paragraph tells us that _________.
A.researchers have understood the bird very well |
B.the bird has a very good sense of direction |
C.there are still many who doubt the bird’s ability |
D.the bird has an inner compass |
A.The great impact and progress in genetic engineering B.Worries about privacy protection C.Worries about medical use of genetic engineering D.Genetic knowledge helps to predict diseases E.Genetic knowledge may not be properly used AB.The application of genetic engineering in the medical fields |
1.__________
Current research into the human gene system is helping us understand why people have predispositions(易患某病倾向)to certain diseases.Knowing our genetic makeup can help us to judge whether or not we may be stricken by particular illness, such as cancer.Even before birth, we are able to do genetic screenings to determine what a child's genetic disorder will be.Scientists have already isolated and identified the genes responsible for the more than 4,000 genetic diseases that affect human beings.
2.__________
The implications of this knowledge are astonishing. In addition to predicting genetic predisposition towards diseases, gene therapies may provide new treatments or cures for serious diseases.Millions of people already use genetically engineered drugs to treat heart disease, cancer, AIDS, and strokes (中风). But with the research that is now being conducted, we may find cures to many more diseases.In the near future, genetic experimentation will also allow parents to select the traits of their children. Genetic traits that determine height, weight, eye and hair color will be able to be controlled, and many parents are excited about this potential.
3.__________
Many people, however, are unwilling to accept the possibilities genetic research allowsFor example, one reason some women do not use the largest genetic testing for breast cancer is because they are afraid they will be discriminated against.Another problem is that many people do not want to discover their weakness.What if they learn that they have a disease for which there are no medical cures? How will such knowledge affect their lives? Do people really want to know what they will die of?
4.__________
Many people believe that history has not always shown human decision-making to be bright when it comes to ethical(道德的)choices. Jeremy Rifkin is probably the most well known opponent of genetic engineering. He believes that humans are not responsible enough to experiment with genes and should not “play God” He asks, “Just because it can be done, does that mean it should be done?” He points out that our society will eventually look and act the same if parents select the traits of their children, and he questions the desirability of such a society.
5..__________
One of the fears expressed about genetic experimentation involves privacy. Already blood sample taken from patients in hospitals have been used for genetic research without the patients’ permission. Most people would agree that one’s health and genetic makeup are private concerns. But if insurance companies gain access to this information, it could have a large impact on insurance coverage or costs; if employers gain access to the information, it could have a large impact on hiring or promotion decisions. The possibilities for discrimination are obvious.