问题 阅读理解

READING COMPREHENSION

     Directions: Read the following three passages. Each passage is followed by several questions or unfinished statements. For each of them there are 4 choices marked A, B, C and D. Choose the one that fits best according to the information given in the passage.

     Everyone has got two personalities — the one that is shown to the world and the other that is secret

and real. You don't show your secret personality when you're awake because you can control your

behaviour, but when you're asleep,  your sleeping position shows the real you. In a normal night, of

course, people frequently change their position. The important position is the one that you go to sleep in.  

     If you go to sleep on your back, you're a very open person. You normally trust people and you are

easily influenced by fashion or new ideas. You don't like to upset people, so you never express your real

feelings. You're quite shy and you aren't very confident.  

     If you sleep on your stomach, you are a rather secretive(不坦率的)person. You worry a lot and

you're always easily upset. You're very stubborn(顽固的), but you aren't very ambitious. You usually

live for today not for tomorrow. This means that you enjoy having a good time.  

     If you sleep curled up(卷曲), you are probably a very nervous person. You have a low opinion of

yourself and so you're often defensive. You're shy and you don't normally like meeting people. You

prefer to be on your own. You're easily hurt.  

     If you sleep on your side, you have usually got a well-balanced personality. You know your strengths

and weaknesses. You're usually careful.  You have a confident personality. You sometimes feel anxious,

but you don't often get depressed. You always say what you think even if it annoys people.        

1. According to the writer, you naturally show your secret and real personality __________.

A. only in a normal night

B. only when you're sleeping

C. only when you refuse to show yourself to the world

D. only when you change sleeping position 

2. Which is NOT mentioned in the second paragraph about a person's personality? 

A. He /she is always open with others.

B. He /she always likes new ideas earlier than others.

C. He /she is always easily upset.

D. He /she tends to believe in others. 

3. Point out which sentence is used to show the personality of a person who is used to sleeping

on his/her stomach? 

A. He /she is always optimistic.

B. He /she doesn't want to stick to his or her opinion.

C. He /she always enjoys his/her real life.

D. He /she often dreams to be a big person. 

4. Maybe you don't want to make friends with a person who sleeps curled up. Why? 

A. He/she would rather be alone than communicate with you.

B. He/she is rarely ready to help you.

C. He/she prefers staying at home to going out.

D. He/she wouldn't like to get help from you. 

5. It appears that the writer tends to think highly of the person who sleeps on one side because ______ . 

A. he /she always shows sympathy for people

B. he /she is confident, but not stubborn

C. he /she has more strengths than weaknesses

D. he/ she often considers annoying people 

答案

1-5: BCCAB

单项选择题
单项选择题

斯坦福大学的科学家们制造出了一种分子扩大了的DNA,其双螺旋结构比自然界已发现的任何一种DNA都要宽。这种大分子DNA不仅耐热性好,而且还能在黑暗中发光——这一特性可能对检查人体基因缺陷十分有用。
DNA的典型形态是双螺旋结构——两组平行的基因信息像一根长长的盘旋的梯子一样联结在一起。每一节梯子都由两个互补的碱基组成,它们组合在一起成为碱基对。
自然界只有4种天然碱基,它们是:腺嘌呤(A),鸟嘌呤(G),胞嘧啶(C),胸腺嘧啶(T)。由于4种碱基各自独特的形态和大小,T常常与A配对,G常常与C配对。其他的配对形式(如A配C,G配T)都会因为太宽或太窄而不能形成双螺旋结构。
人类DNA由约30亿个碱基对按特定顺序排列组成,它们将人类健康生存所需要的基因信息拼写出来。只要一两对碱基对的排列顺序出错,基因密码就会出现混乱,从而导致婴儿在出生时会出现可怕的畸形或导致像癌症和镰状细胞贫血症这样的疾病。
加利福尼亚理工学院的化学家纳尔逊·伦纳德在20世纪70年代做过一个实验,他将一个苯环嵌入碱基A,得到了一个大碱基xA,xA比普通碱基A宽了约33%。斯坦福大学的科尔和他的同事们继续了伦纳德的实验。
斯坦福大学的这个研究组使用与伦纳德相似的方法得到了xT——一种大小为自然T两倍的合成碱基。接下来的挑战是将这些大碱基嵌入双螺旋结构。
他们通过将xA与自然T组合,xT与自然A组合,从而合成了完美的双螺旋结构。一种比自然DNA宽了约20%的新的稳定的DNA形态诞生了,研究人员将它命名为“扩展DNA”或“xDNA”。
研究人员发现xDNA有几个比自然DNA更加优良的特点。比如说,xDNA比自然DNA的耐热性好。在实验室环境下,自然DNA的分解温度是21.3摄氏度,而xDNA在55.6摄氏度时还依然保持完整。
科尔说:“一般说来,体积大的物体比体积小的物体耐热性好,DNA也不例外。”
他补充说,大一些的分子一般会发出荧光,这也许能解释为什么自然DNA不发光,而xDNA却发出一种紫色光,使它在显微镜下被看得很清楚。
在自然界,DNA携带了所有的遗传信息并传给后代。科尔正在研究xDNA是否也有这种功能。
不过他警告说:“这种新的DNA不太可能在地球上的自然环境中发挥功能,因为它太大了。不过,我们希望,有一天它会成为地球上或是其他星球上的一种新的生命形式的基因物质,这样当我们往其他星球上派探测机器人时,我们就会知道要在冰层下寻找什么样的生命形态。”

根据原文提供的信息,以下推断不正确的一项是______。

A.一般说来,体积大的物体比体积小的物体耐热性好,这一规律可以解释xDNA比自然DNA耐热性更好的现象
B.大一些的分子一般会发出荧光,DNA也不例外,这就可用来解释xDNA与自然DNA在发光问题上的差异
C.因为xDNA太大了,科尔认为它在地球上的自然环境中发挥功能的可能性不大
D.如果xDNA将来能成为地球上或是其他星球上新的生命形式的基因物质,它就会为我们的太空生命探索提供指导