题目

 阅读理解 Canaries (small yellow songbirds) are more sensitive to carbon monoxide (CO) than people are. Thus they were routinely taken into mines as men went about their work of mining for coal. CO could quickly poison many miners before they even knew what was happening. If a Canary stopped singing, this was an indicator of rising CO levels. Now ecologists think they've found a "canary" that could predict possible disaster for tropical (热带的) ecosystems — the cricket (a small brown jumping insect). Crickets are tiny, present in large numbers and, most importantly, noisy. The chirps (唧唧叫声) of individual species are identifiably different. Researchers had previously wondered if ecosystems might be monitored by listening to how the sounds of their crickets change over time. Amandine Gasc and her colleagues studied cricket populations on Grande Terre Island in New Caledonia, where multiple ecosystems often exist very near to each other. They collected crickets at 12 sampling sites. Four were healthy forest sites, four were shrubland (灌木地) areas, of the sort that is often created when people cut down forests, and four were shrubland areas that were turning into forests again. They listened for insects in square zones and ran ten 30-minute collection sessions (five in the day and five at night) at each site. Dr. Gasc described how each ecosystem had, in effect, a distinct "cricket fingerprint". Species richness varied considerably among the different environments. Of the 20 cricket species found in the healthy forest, 12 were unique to that habitat alone, 2 of the 15 species found in transitioning forests were unique to this habitat and 3 of the 7 shrubland species were unique to shrubland. Just by looking at the crickets found in a given location, the team found that it was possible to determine whether they were looking at shrubland, forest or shrubland that was changing into the forest. There was no need to examine the other surrounding plants or animals. What's more, Dr. Gasc's team found each habitat contained cricket species that generated their identifiable chirps. This suggests that setting up audio recorders in forests that pick up cricket calls will be an easy, cheap and accurate way to detect the early stages of change in tropical ecosystems. （1） Why did miners take the canary into mines? A . To bring down CO levels. B . To promote their work efficiency. C . To offer them some entertainment. D . To remind them of the potential danger. （2） How did Dr. Gasc and her colleagues carry out their study? A . By analyzing "cricket fingerprints". B . By comparing plants in different zones. C . By observing the changes in landscapes. D . By referring to previous findings on crickets. （3） What conclusion may Dr. Gasc and her colleagues draw from their study? A . Healthy forests may attract fitter crickets. B . Crickets are suitable to be indicators in mines. C . Different species of crickets may sound different alarms. D . The species of crickets are strongly related to the environment. （4） Which of the following can be the best title for the text? A . Canaries: miners' good helpers B . How crickets are distributed in tropical areas C . Crickets: an early indicator of tropical ecosystem health D . Why cricket chirps are collected on Grande Terre Island 答案： D A D C

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