下列二次根式中，与$\sqrt{6}$的乘积为有理数的是（　　）

阅读下面短文，掌握其大意，然后从各题所给的A、B、C和D项中，选出最佳选项。

         What happened to that brilliant idea that you once had? Did you  1  it because you thought that it was just a little thought? Have you ever   2 what that little thought would have become if you had acted on your instincts 3  if you had paid more attention to it?

         Imagine a   4  , where you are sitting at home watching television or reading a book, suddenly a light is   5  on in the dark tunnel of your mind as a thought or an idea crosses your mind. The thought   6   your attention but seems so meaningless and you are tempted to   7   it, but wait a minute! That thought could be the potential beginning of the   8   you have so much wished for.

         As the thought crosses your mind, your senses become alert and you suddenly see a possibility, a solution, or find the answer to a problem whose solution has  9    escaped you. It is almost as if a wise man has   10   the perfect solution into your ear or awakened your senses to a reality, thereby bringing light to your life. It is like finding the   11   piece of jigsaw puzzle(拼图游戏). This becomes an amazing moment and everything freezes around you as you excitedly try to grasp the practicality of that   12  but powerful thought.

         Your self­confidence and enthusiasm increase as you become  13   of the great possibilities that can   14   if that little thought is acted upon. This becomes the moment to build upon that thought and to put  15   any ideas that are streaming from that little thought for later review.   16   meaningless little thoughts or ideas, when acted 17，  have a potential to explode into great projects. Many successful projects have been 18   from the little positive thoughts that were carefully protected and recognized as bricks to great things.

         Don't waste a(n)   19  to act on a potentially brilliant idea. You don't have to wait for a major idea, or approval from your peers in order for you to act on that little thought.

         That little thought or idea is the  20  of great things if you decide to follow it through.

材料一：瑞士境内阿尔卑斯山横亘全国，风景优美，湖泊众多，享有“世界花园”美誉。贵州省“地无三里平”，旅游资源丰富多样，拥有“公园省”之称。尽管瑞士和贵州相隔万里且经济发展程度不同，但是两地在自然地理环境、交通区位等诸方面有相似之处。近年来，贵州希望借鉴瑞士的发展经验，促进贵州产业结构的升级和优化，借鉴学习发展成为“东方瑞士”。

材料二：下图为瑞士和贵州地形图

 材料三：下表为瑞士和贵州的产业结构

阅读《花开的声音》一文，回答下列各题。

花开的声音

陈文和

       花开也有声音么？

       一个夏季的晚上，我在住家的阳台上，就捕捉到昙花开放的声音。那棵昙花的花苞早在两三天前就显露出了雏形，这个“雏形”的花苞越来越大，在枝头垂首有如纺锤。那一夜，我估摸它会开放的，便在阳台彻夜守护着，耐心地等待，等待。近午夜十一时，那美好的时刻终于在焦灼的期待中来到了。它的花苞慢慢地鼓胀起来，好像原先干瘪的汽球一下子灌进了风，紧接着，我便听到一声“噗”的响动，那是我盼望已久的昙花开放的声音。只见那由许多纤长洁白的花瓣组成的花蕊，快速、灿然地开放了。 痴迷间，眼前仿佛跳出了一个长袖善舞的倩女，只一刹那，便羞煞了天际那半轮夏月，那美的光焰，撒向城市街道，使夜的峡谷为之闪闪发亮。。

       除了昙花，我还真切地听到茶花开放的声音。茶花的开放可不是那种“急性子”，早在夏季时，它的蓓蕾就在枝叶间开始孕育，开头只有一粒米那般大小，和叶芽的形状几乎难以分辨，过了好几天，它的雏形才微微显露出来，又再好几天，它那结实的体态和叶芽松动的体态才泾渭分明。茶花花苞的长大，是一个漫长的过程，就像一个长途旅者，走过了夏天，又走过了秋天，到了冬季，那一头尖的椭圆花苞，那花瓣如鳞片重重包裹的花苞，才终于展现在你的面前，但距离开放仍有些日子。我栽在阳台的那一株茶花，叫“五宝茶花”，枝头共有十几个花苞，它们之间好像有个约定，谁先开谁后开。那一天是休息日，我终于看到第一颗准备开放的花苞有些异样了，它在微微地颤动、颤动，仿佛是个睡美人，在阳台上睡了许久、许久，此刻才在深绿色的枝叶间苏醒，惺忪的眼眸，抖动的睫毛，微微地张开，张开。那张开的声音，和昙花的那一声“噗”完全相反，它是那么细微，那么柔和，那么舒缓。昙花开放的声音是短促的，茶花开放的声音是悠长的，不管短促或悠长，都是那么动听，那么迷人。由此我认定：花开的声音是自然界一种最美妙的乐曲，或者说是一种天籁吧！

       花儿这样，世界上一切美好的事物何尝不是如此。当它突然出现时，也会有一种异样的信息，一种类似花开的声音，那是一种文明之花开放的声音。美好事物的孕育、萌发、成熟，也有个渐进的过程，或许中间还会出现一波三折，受到某种压抑和禁锢。当它“破茧而出”或“破墙而出”时，会出现多大的冲击波啊，那一瞬间闪亮的冲击，给人带来的是一种无限的惊喜。这种声音，你只有保持一份纯净、洁白的心态，于细微处才能听到。对于美好的事物，不要有疏离感，要把它置于自己的关爱之下，用自己的羽翼和体温去为它孵化和催生，这样，你就可以及时地听到另一种“天籁”了。

       长时间以来，我都迷恋于谛听各种花开的声音。我始终认为，在人世间，倾述是一种方式，谛听也是一种方式。一个人能听到花开的声音是十分幸福的，因为花开的那一刹那，会最充分地展开事物的内秀和外美，会给你带来一种审美的愉悦和情感的满足。

（选自2011年第1期《南方》，有改动）