Clark, director of the bioacoustics research program at Cornell University, the area over which whales in coastal waters can hear one another shrinks to only 10 to 20 percent of its natural extent.
By combining the special natural conditions in karst mountain area, the necessity and importance in strengthen the research on soil tillage erosion is put forward.
本文还结合岩溶山区特殊的自然环境条件，提出了加强岩溶山区土壤耕作侵蚀研究的必要性和重要意义。
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The natural landscape simulation is an important researcharea of computer graphics.