1. The word “descent” in the passage means ________.

A. taking off　 B. landing 　　 C. orbiting 　　 D. walking down

5. A。主旨题。综合文章内容，不难概括出本文主旨：解读基因密码。

(3)

The space shuttle Columbia flared and broke up in the skies over Texas on Saturday, February 1,2003, killing the seven astronauts on board in what NASA and President Bush called a tragedy for the entire nation. NASA launched an investigation into the disaster and began searching for the astronauts' remains. It said that although there had been some data failures it was too early to nail down a precise cause. The break-up, 16 minutes before the shuttle was due to land at Kennedy Space Center in Florida, spread possibly toxic debris(有毒的残骸) over a wide swath of Texas and neighboring states.

Dramatic television images of the shuttle's descent clearly showed several white trails(痕迹) streaking through blue skies after the shuttle suddenly fell apart. It was almost 17 years to the day that the Challenger shuttle exploded on Jan. 28, 1986, killing all seven astronauts on board.

Take-off and re-entry into Earth's atmosphere are the most dangerous parts of a space mission. In 42 years of US' human space flight, there had never been an accident in the descent to Earth or landing. Challenger exploded just after take-off.

Rescue teams scrambled to search for the remains of the crew, which included the first Israeli to fly on the shuttle, former combat pilot Col. Ilan Ramon. There were warnings that parts of a vast 120-mile-long corridor of debris could be toxic because of poisonous rocket propellant(推进器).

"We are not ready to confirm that we have found any human remains," Nacogdoches County Sheriff Thomas Kerrs said. He added that among the roughly 1,000 calls reporting debris, some people said they found remains of crew members.

"The Columbia is lost. There are no survivors, …Their mission was almost complete and we lost them so close to home. … America's space program will go on," said a grim-faced Bush in a message broadcast on television, which included condolences to the families of the dead astronauts.

4. B。判断题。从文章内容可知，人类基因组图的完成将有助于科学家们攻克一系列难关。所以，他们在更努力地探究。

3. D。判断题。美国是在 1990 年，即 20 世纪末开始绘制人类基因组图的，所以选项D 不对。

2. C。细节题。因为 …the leading organization for genetic research is in the United States,所以答案选 C。

1. B。语义理解题。从文章最后一段第1句话Once these genes are found and studied, researchers can develop new ways to attack infections(传染), and genetic diseases 可以看出科学家们完成人类基因组图的目的。

5. The main idea of this article is about _______.

A. unlocking genetic code

B. the genes' discovery

C. the great human genome

D. the genes and the scientists

[答案解析]

绘制人类基因组图，这将意味着人类消灭癌症、艾滋病的危害，延长人类寿命将成为现实。

4. The author suggests that the Human Genome Project can cause _______.

A. the policy makers to feel very worried and careful

B. the scientists to work harder

C. many people to find work easily

D. a lot of companies to produce many new drugs

3. Which of the following is NOT true?

A. If the genes can be found, scientists can study many new ways to cure illnesses.

B. The scientists have made great progress in connecting the genes with the cancers.

C. Many medical companies show great interest in drawing the human genome map.

D. The United States began the Genes Study early in the 19th century.

2. Which country studied the genes most rapidly in the world?

A. Japan.　　　　 B. Germany.　　　　　 C. The United States.　　 D. China.