Question

13．US scientists have performed an important reversal（逆转） of the ageing process in animal studies．They used a chemical to rejuvenate（使年轻） muscle in mice and said it was the equivalent（等同于） of transforming a 60-year-old's muscle to that of a 20-year-old-but muscle strength did not improve．Their study，in the journal Cell，identified an entirely new mechanism（原理） of ageing and then reversed it．Other researchers said it was an"exciting finding"．
Ageing is considered a one-way street，but now researchers at Harvard Medical School have shown that some aspects can be reversed．Their research focused on a chemical called NAD．Its levels naturally drop in all cells of the body with age．The team showed this damaged the function of the cell's in-built power-stations，leading to lower energy production and ageing．
Experiments showed that increasing NAD levels，by giving mice a chemical which they naturally change into NAD，could reverse the sands of time．One week of youth-medication in two-year-old mice meant their muscles became similar to those of a six-month-old．
Dr Ana Gomes，from the department of genetics at Harvard Medical School，said："We believe this is quite an important finding．"She argues muscle strength may return with a longer course of treatment．However，this could never be a cure-all for ageing．Other aspects such as shortening of telomeres or damage to DNA would not be reversed．
Dr Gomes told the BBC："Ageing is multi-factorial，it's not just one component（成分） we can fix，so it's hard to target the whole thing．I believe there is a lot of cross-talk in cells and energy is very important in a cell and likely to be a very big component of ageing that might cause some of the other things that happen with ageing．"
68．From paragraph 1 we learn thatD．
A．bones can be transformed
B．muscle strength can be transformed
C．color can be transformed
D．muscle can be transformed
69．From paragraph 2 and paragraph 3 we learn thatC
A．researchers think ageing is a one-way street．
B．NAD levels'dropping could make mice become younger．
C．increasing NAD levels could make mice become younger．
D．researchers think any aspect can be reversed．
70．Dr Gomes will agree thatB
A．we can target everything about ageing．
B．muscle strength may return over a longer course of treatment．
C．ageing could be cured．
D．energy is of little importance in a cell．

Answer 1

分析 本文是一篇科教类阅读，主要讲的是一个令人振奋的"可以逆转老化过程"的发现．

解答 68-70．DCB
68题答案：D考查细节推理，根据第一段的They used a chemical to rejuvenate（使年轻） muscle in mice and said it was the equivalent（等同于） of transforming a 60-year-old's muscle to that of a 20-year-old-but muscle strength did not improve．（他们使用一种化学物质来使老鼠的肌肉年轻化并且说这等同于将60岁老人的肌肉变成20岁年轻人肌肉--但是肌肉的力量没有提高）．可知本题答案为D选项．
69题答案：C考查细节推理，根据第三段的Experiments showed that increasing NAD levels…could reverse the sands of time．试验表明增加NAD的等级可以逆转时间．可知提高NAD的等级可以是老鼠变年轻，故本题答案为C选项．
70题答案：B考查细节推理，根据文章倒数第二段的She argues muscle strength may return with a longer course of treatment．她提出理由证明肌肉的力量在长期的治疗后可以恢复．可知本题答案为B选项．

点评 本文是一篇科教类阅读，题目涉及多道细节理解题，做题时结合原文和题目有针对 性找出相关语句进行仔细分析，结合选项选出正确答案．推理判断也是要在抓住关键句子的基础上合理的分析才能得出正确的答案．