2014年9月我们走进了中学，成了一位中学生，我们要努力做一个阳光少年。这就要求我们（  ）

依次填入下列各句横线处的词语．最恰当的一组是（    ）

  ①这是一张不同一般的弗拉门哥吉他专辑，动听悠扬的旋律，令人振奋的舞蹈般的节

奏，处处      着西班牙特有的狂野气息．使吉普赛民族的豪放特性得到了完美展现。

  ②课程考核成绩一经评定．任何人不得随意更改，如有特殊情况须更改者，由评定成绩

的教师向教务主管领导     理由，经研究同意后才能更改。

  ③熊猫如能顺利来台，不但可让台湾民众近距离接触可爱的熊猫，又       不是开启

双方良性互动的另一契机?

RNA是生物体内最重要的物质基础之一，它与DNA、蛋白质一起构成了生命的框架．近年科学家发现，一些RNA小片段能够使特定的植物基因处于关闭状态，这种现象被称作RNA干扰（RNAInterference，简称RNAi）．近日，分子生物学家发现RNAi在老鼠和人体细胞中也可以“停止基因活动”．根据上述材料回答：

（1）老鼠细胞的细胞核、____ 、____ 、细胞质基质等结构中有RNA的分布．

（2）RNAi使基因处于关闭状态，是遗传信息传递中的____ 过程受阻，遗传信息不能以蛋白质的形式表达出来．如胰岛A细胞有与合成胰岛素相关的基因也有与合成胰高血糖素相关的基因，但只能产生____ ，结合以上材料，分析其可能原因是：____．

（3）过去的很长时间内，科学家一直认为，RNA仅仅是传递遗传信息的信使．列举一例，说明“RNA也可以是控制生物的性状的遗传物质”：____ 

Dear Wang Tao,

    I'm so glad to read about the changes taking place in your city. I am happy that you can travel by subway in Chongqing, though there are only six lines there. Here is London we have twelve lines.

    The London Underground is very famous. It's famous for several reasons. Firstly, part of the underground railway today is the oldest in the world. It opened in 1863. Secondly, the London Underground is also the first line to have electric（电动的）trains in 1890. Thirdly, the London Underground is the second largest metro（地下铁道）system in the world, after the Shanghai Metro. There are 270 stations in the Underground and it has 402 kilometers of tracks (轨道). What's more, the city of London itself helps make the transportation（交通）system famous! I've got a few photos to help you build a clear picture of the Underground in my city. They are together with this mail.

    In your e-mail, you also said workers were building more lines. I'm sure your city is developing fast. Maybe you can send me a few photos of your city today. I really want to see the changes taking place there. I'm happy for you to live in an ancient city with such a new look!

    So much for now. I'll write soon again. Best wishes!

Yours,John