真核生物的mRNA应该是（） A.在胞质内合成和发挥其功能 B.帽子结构是一系列的腺

Do you dream of being a reporter or an editor? Are you a good writer who loves the news? If so, then you may have what it takes to be a winner in the TFK Kid Reporter Talent Search.

We’re looking for 12 students from around the nation to be members of the TFK Kid Reporter Team for the 2008-2009 school year. Next year’s team will continue the tradition of reporting local and regional news stories for TIME FOR KIDS magazine and TIME FOR KIDS online.

Professional（职业的）journalists from TIME magazine and TIME FOR KIDS will select this exclusive team. In the past, TFK kid Reporters have

Interviewed national leaders, celebrities and other newsmakers.

Written news stories, reviews and opinion pieces for TIME FOR KIDS.

Appeared on CNN, Fox News, MSNBC, Today and The Tonight Show with another famous kid Jay Leno to talk about their work.

How to Enter

Get the official rules at time for kids. com/contest.

Entries must be postmarked by Dec. 20, 2008. Good luck!

53. This ad is written for ___________________.

A. professional reporters and editors

B. student reporters and editors

C. kids who are interested in politics

D. kids who love to write news

54. If you want to become a TFK Kid reporter, you must _________________.

A. write news stories for local newspapers

B. sign up through TFK’s official website

C. post your entries before Dec 20, 2008

D. know a lot about the newspaper and its style

55. Winners of the talent search will be able to do all the following EXECPT _____.

A. write reports on celebrities and other newsmakers

B. become a professional journalist for TIME magazine

C. write down their opinions for TIME FOR KIDS

D. share their working experiences with other kids on famous media

细菌实验室必须具备的设备，不包括（）

A.恒温培养箱

B.高压蒸气灭菌器

C.显微镜

D.低温离心机

E.冰箱

含有机酸的药物与哪项合用会失去治疗作用（）

A.维生素

B.四环素

C.含溴化物的制剂

D.碱性药物

E.铝镁钙药物

人的行为的特点有（）。

A.具有适应性

B.具有多样性

C.具有动态性

D.具有可控性

E.实质是人的生理、心理因素与客观环境相互作用的结果和表现

Despite the fact that comets are probably the most numerous astronomical bodies in the solar system aside from small meteor fragments and the asteroids, they are largely a mystery. Scientists do not know exactly what comets are or where they come from. Educated guesses are the best we have in hand.

Considering the role of comets in legend and the memory of man, it is remarkable that we still know so little, relatively, about them. The most famous comet of all, Halley’s Comet ( named for the man who predicted its return), was first sighted by the Chinese in 240 B．C．, and it has returned to terrify the people of the world on a regular basis every since then. The ancient considered it an object of ill omen. By mysterious coincidence, the arrival of Halley’s Comet coincided with such events as the battle of Hastings in 1066, the Jewish revolt of 66 A．D．, and the last battle of Attila the Hun against the Romans. Nor is it the only comet to fill man with awe, but merely the most famous in a rich aristocracy of blood-freezers.

Comets are even more fascinating to amateur astronomers than to professionals, because this is one area where amateurs can make major discoveries. Comet Ikeya Seki, one of the brightest comets to appear in this century was discovered in 1965 by a pair of Japanese amateurs, Ikeya and Seki. The person who discovers a new comet gets his (or her) name put on it. And amateurs have a head start in the race to discover new comets; the shorter focal lengths on their smaller telescopes give them a positive advantage over the huge telescopes such as Mount Wilson which is built to scan for galaxies, not comparatively short distances.

Most scientists tend to agree with astronomer Fred T. Whipple that a comet is really a large mushy snowball of frozen ices and gases ( ammonia, methane, possibly carbon dioxide) with a few bits of solid particles stuck inside. But no one is sure how comets are created in the first place.

Scientist believe that comets don’t exhibit their characteristic tail while they lurk fat out in space away from the warmth of the sun but, rather, wander in the form of frozen lumps, like icebergs. This is the core of the comets. Only when the comet approaches the heat of the sun, does the ice begin to melt and stream away in the form of visible gases. The tails of the comets stream out behind for, literally, astronomical distances. Halley Comet had a tail of 94 million miles long when it visited here in 1910．The Great Comet of 1843 had a tail of 186 million miles long.

We learn from the text that amateur astronomers（）

A. began their discovery earlier than the professionals

B. tend to be the leaders in the area of astronomy

C. have some advantages in discovering new comets

D. established some theories on how comets come into being