托福阅读考试双语：一切都开始于一个细胞.docxVIP

Word文档下载后（可任意编辑） 第 第 PAGE 1 页 共 NUMPAGES 1 页 托福阅读考试双语：一切都开始于一个细胞 托福考试备考素材：托福阅读考试双语：一切都开始于一个细胞 雅思考试精品课程推荐  DIANE MILLEY, a teacher, remembers getting the small, dry cough just before school broke up(词汇)for the summer in 2013. She wasn’t worried: she considered herself generally healthy—she ran three times a week and went to the gym. Her doctor in Bradford, Massachusetts, put her on a course of antibiotics. When they didn’t work she had an X-ray. It showed nodules(词汇)across her lungs. A bronchoscopy(词汇)was ordered to retrieve a tissue sample(词汇) from her lung. As she came round from the anaesthetic she remembers overhearing two medical staff talking. One said “It’s malignant.” She had late-stage lung cancer.  戴安·米莉(Diane Milley)是一名教师。她记得2013年夏天学校临放假前，她开始轻微的干咳。她并没有放在心上——她觉得自己总体上很健康，每周跑步三次还去健身房。马萨诸塞州布拉德福德的医生对她用了一个疗程的抗生素。治疗无效后她拍了一张X光片，显示她的肺部存在结节。随后医生让她做支气管镜检查，从她的肺部提取组织样本。当她从麻醉中醒来时，听到两名医务人员在说话。其中一人说：“是恶性的。”她患的是晚期肺癌。  Ms Milley’s body, like all human bodies, contained tens of trillions of copies of her genome. In theory, all those copies should be more or less the same. In practice, over the years, they all get knocked around(句型) in different ways. The oxygen that powers cell metabolism(词汇)damages the DNA on which the genes are stored as a matter of course; so do background radiation and exposure to the many low-level carcinogens(词汇); so do sunlight and infection with viruses; so do choices about diet and recreational drugs(词汇), notably alcohol and tobacco (from which Ms Milley abstained).  和所有人的身体一样，米莉的身体也含有自身基因的数十万亿个副本。理论上说，所有这些副本都应该是基本相同的。然而实际上，经年累月，它们以不同的方式遭到了破坏。为细胞代谢提供能量的氧会自然而然地破坏存储基因的DNA，背景辐射和接触许多低级致癌物也会如此，日晒和病毒感染也会如此，饮食选择和娱乐性药物，特别是酒精和烟草(米莉均不沾)，也会如此。  The vast bulk of(句型)this damage is quickly fixed by DNA-repair enzymes; fewer than one mutation in a thousand persists. But wear and tear builds up. Many such changes make little or no difference. A few will be of consequence to(句型)the cell concerned, reducing or eliminating its cap