7. “There is a trade-off（平衡） between the diagnostic（诊断的，判断的） benefits of breast screening and its risks,” admits Michael Clark of the NRPB. But he warns that the study should be interpreted with caution. “On the basis of the current （目前的）data, for every 10 cancers successfully detected and prevented there is a risk of causing one later in life. That’s why radiation exposure should be minimized in any screening programme.” 练习：
1. Paragraph2 ___A_____ 2. Paragraph3 ___B_____ 3. Paragraph4 _ _C___ 4. Paragraph5 ___D__
A. Harm Screening May Do to a Younger Woman B. Investigating （调查）the Effect of Screening C. Effects Predicted by Two Different Models D. Small Risk of Inducing Cancers from Radiation E. Treatment of Cancers F. Factors That Trigger Cancers
5.Early discovery of breast cancer may____C____. 6.Advantages of screening women under 50 are __D_____. 7.Delaying the age at which screening starts may ___E_____.
8.Radiation exposure should be ___F_____. A. be costly B. harmful C. save a life
D. still open to debate(争论)
E. reduce the risk of radiation triggering a cancer F. reduced to the minimum
The Mir space station
1. The Russian Mir Space Station, which came down in 2001 at last after 15 years of pioneering the concept of long-term human space flight, is remembered for its accomplishments in the human space flight history. It can be credited with many firsts in space.
2. During Mir's lifetime, Russia spent about US$4.2 billion to build and maintain the station.
3. The Soviet Union launched Mir, which was designed to last from three to five years, on February 20, 1986, and housed 104 astronauts over 12 years and seven months, most of whom were not Russian. In fact, it became the first international space station by playing host to 62 people from 11 countries. From
1995 through 1998, seven astronauts from the United States took turns living on Mir for up to six months each. They were among the 37 Americans who visited the station during nine stopovers by space shuttles.
4. The more than 400 million the United States provided Russian for the visits not only kept Mir operating, but also gave the Americans and their partners in the international station project valuable experience in long-term flight and multinational operations.
5. A debate continues over Mir’s contributions to science. During its existence, Mir was the laboratory for 23,000 experiments and carried scientific equipment, estimated to be worth $80 million, from many nations. Experiments on Mir are credited with a range of findings, from the first solid measurement of the ration of heavy helium atoms in space to how to grow wheat in space. But for those favouring human space exploration, Mir showed that people could live and work in space long enough for a trip to Mars. The longest single stay in space is the 437. 7 days that Russian astronaut Valery Polyakov spent on Mir from 1994 to 1995. And Sergie Avdeyev accumulated 747.6 days in space in three trips to the space station. The longest
American stay was that of Shannon Lucid, who spent 188 days aboard Mir in 1996.
6. Despite the many firsts Mir accomplished, 1997 was a bad year out of 15 for Mir. In 1997, an oxygen generator caught fire. Later, the main computer system broke down, causing the station to drift several times and there were power failures. 7. Most of these problems were repaired, with American help and suppliers, but Mir's reputation as a space station was ruined. 8. Mir’s setbacks are nothing, though, when we compare them with its accomplishments. Mire was a tremendous success, which will be remembered as a milestone in space exploration and the space station that showed long-term human habitation in space was possible. But it's time to move on to the next generation. The International Space Station being built will be better, but it owes a great debt to Mir.
More rural research is needed
1. Agricultural research funding is vital if the world is to feed itself better than it does now. Dr. Tony Fischer, crop scientist, said demand was growing at 2.5% per year, but with modern technologies and the development of new ones the world
should be able to stay ahead.
2. “The global decline in investment in international agricultural research must be reversed if significant progress is to be make towards reducing malnutrition and poverty, ” he said.
3. Research is needed to solve food production, land degradation and environmental problems. Secure local food supplies led to economic growth which, in turn slowed population growth. Dr. Fischer painted a picture of the world's ability to feed itself in the first 25 years, when the world's population is expected to rise from 5.8 to 8 billion people. He said that things will probably hold or improve but there'll still be a lot of hungry people. The biggest concentration of poor and hungry people would be in sub-Saharan Africa and southern Asia in 2020, similar to the current pattern. If there is any change, a slight improvement will be seen in southern Asia, but not in sub-Saharan Africa. The major improvement will be in east Asia, South America and South-East Asia. 4. The developing world was investing about 0.5%, or $8 billion a year, of its agricultural gross domestic product (GDP) on research, and the developed world was spending 2.5% of its GDP. Dr Fischer said more was needed from all countries.