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导语：以下英语网为大家整理了全面的职称英语考试历年真题及答案解析，《职称英语考试试题汇总：历年真题及答案解析》供大家参考学习。更多职称英语考试试题敬请关注英语网！ 【推荐】关注英语网微信：yingyuwang2013，更快获取真题答案及成绩查询信息。 第 4部分:阅读理解 (第 31~45题,每题 3分 ,共 45分) 下面有3篇短文，每篇短文有5道题。请根据短文内容，为每题定1个最佳选项。 第一篇 Human Heart Can Make New Cells Solving a longstanding mystery, scientists have found that the human heart continues to generate new cardiac cells throughout the life span, although the rate of new cell production slows with age. The finding, published in the April 3 issue of Science, could open a new path for the treatment of heart diseases such as heart failure and heart attack ,experts say. We find that the beating cells in the heart, cardiomyocytes, are renewed,said lead researcher Dr. Jonas Frisen, a professor of stem cell research at the Karolinska Institute in Stockholm, Sweden. It has previously not been known whether we were limited to the cardiomyocytes we are bom with or if they could be renewed. he said. The process of renewing these cells changes over time, Frisen added. In a 20-year-old, about 1 percent of cardiomyocytes are exchanged each year, but the turnover rate decreases with age to only 0. 45 percent by age 75. | 
