| Antibiotic resistance doesn’t just
make pathogens(病原体) difficult to treat, It also makes them harder to track
Traditionally, epidemiologists(流行病专家)following the paths of disease-causing
microbes have identified their suspects by features of bacterial
polysaccharide(多糖) coats, susceptibility to different antibiotics, or other
schemes But these tracking techniques "are losing their relevance (相关性,实用性),
"says Alexander Tomasz, a microbiologist at Rockefeller University in New York
City. With the increase in drug resistance, a variety of resistant microbes can
now wear the same coat or be resistant to the same drugs, making it harder and
harder to keep tabs on individual strains (菌株). Epidemiologists, therefore, are increasingly turning to more precise molecular typing techniques, such as DNA fingerprinting, to distinguish resistant strains. [单项选择]Although Beethoven could sit down and make up music easily, his really great compositions did not come easily at all. They cost him a great deal of hard work. We know how often he rewrote and corrected his work because his notebooks are still kept in museums and libraries. He always found it hard to satisfy himself.
When he was 28, the worst difficulty of all came to him. He began to notice a strange humming in his ears. At first he paid little attention; but it grew worse, and at last he consulted doctors. They gave him the worst news any musician can hear: he was gradually going deaf. Beethoven was in despair; he was sure that he was going to die. He went away to the country, to a place called Heiligenstadt, and from there he wrote a long farewell letter to his brothers. In this he told them how depressed and lonely his deafness had made him. "It was impossible for me to ask men to speak louder or shout, for I am deaf," he wrote. "How could I possibly admit an infirmity in A. was very frightened B. was unhappy C. had given up hope D. was dying 我来回答: 提交
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