( C )

How the Grand Canyon was created remains one of the geology’s greatest mysteries. Some evidence suggests that the process was a gradual one in which the Colorado River (which runs through the canyon) slowly cut deeper and deeper into the ground over millions of years. But volcanic(火山的) rock samples taken from the canyon(峽谷) now suggest that the canyon was downcut instead.

Downcutting is when a flood of water rushes over a landscape with enough force to cut deeply into the ground and leaves behind a canyon. Such a flood is usually released when a natural or artificial dam bursts.

Robert Webb, a research geologist with U.S. Geological Survey, says natural dams seem to have formed and broken across the Colorado River several times during the last million years. The dams were built when lava(熔巖) from the eruptions(爆發(fā)) of nearby volcanoes flowed into the river. The lava hardened into hard rocks and blocked the river, causing it to back up and form a lake. Each time the lake grew so huge that it broke the rock dam, releasing a flash flood that furthered the downcutting process and deepened the canyon. The most recent dam break happened 165,000 years ago, says Webb, and released 15 million cubic(立方) feet of water per second.

Downcutting is not just an earthly event. Satellite photos sent back from Mars (a planet) suggest that the process has happened there, too, say researchers at the National Air and Space Museum.

The photos, taken by the Mars Global Surveyor, indicate that an enormous lake existed on Mars 3.5 billion years ago. The lake, which was big enough to flood Texas and California, eventually spilled into a large nearby hole. One edge of the hole broke, releasing a flash flood that quickly carved out a grand canyon about 2,100 meters deep and 885 kilometers long. Astronauts call the canyon MA’adim Vallis.

The existence of downcutting on Mars is just one more piece of evidence that the cold, dry planet was once warm and wet.

72. In the past, deep canyons were believed to have formed ___________.

A. as a result of a sudden break of volcanoes

B. due to river flows over millions of years

C. owing to the collapse of artificial dams

D. thanks to our ancestors’ creative work

73. From the passage we can guess that ___________.

A. several volcanoes broke out in the Colorado River

B. several great lakes existed on the upper parts of the Colorado River

C. people built high dams on the upper parts of the Colorado River

D. the Colorado River crossed the Grand Canyon millions of years ago

74. From the last three paragraphs we learn that __________.

A. there are great lakes on Mars

B. there are active volcanoes on Mars

C. there might be cities on Mars

D. there might be life on Mars

75. The passage can be titled as _________.

A. Lakes on Earth and Mars

B. The Cause of Lake Formation

C. The Force of Dam Breaking

D. Canyons—Results of Flood Cutting

Section C

Directions: Read the following text and choose the most suitable heading from A-F for each?paragraph. There is one extra heading which you do not need.?

76.

Home is a place where one feels safe and secure but unfortunately, it is also the place where you may have serious accidents. The biggest single cause of accidents is human error! So you must take care of yourself!

77.

The design of houses can cause accidents. Balconies, fireplaces, staircases, ponds, glass doors or open-plan kitchens can all increase the risk of accidents. Hot water, household chemicals, fireplaces, matches, alcohol and sharp objects are also potential dangers. Loosing balance, clumsiness and being tired or careless can be the reasons for these accidents. What’s more, if you are under stress or when a routine is changed, you may also be under the risk of home accidents.

78.

You can see many dangerous home accidents happening around you. The most common ones are slips, falls and collisions. They are not fatal but often result in broken bones. The second most common types of accidents are burns, swallowed objects or breathed in chemicals. They especially affect children and need hospital attendance. Some other possible dangers at home are poisoning, choking, drowning, electric shocks, and animal bites. Some of these accidents may even result in death.

79.

Sometimes the simplest precaution protects you from the greatest harm! Therefore, it is important that we should educate people. The Ministry of Health can train professionals to educate nursing staff, ordinary people, voluntary workers, teachers, nursery staff and parents in home accident prevention and control. When people know first aid, they can reduce the risk of serious injuries.

80.

You must take measures to make your home a safer place. For instance, keep knives and other sharp objects in a safe drawer. Wipe up any liquids on the floor immediately in order not to slip or fall. Keep hot objects away from the reach of children. You also mustn’t leave children unattended near a bath that has water in it. If you keep furniture away from windows, you may prevent possible harm. Store all medicines, household chemicals, and so on, preferably in a locked box and do not forget to keep all dangerous substances in their original containers. In brief, if you want to protect yourself, be careful not to be sorry!

Section D

Directions: Read the passage carefully. Then answer the questions or complete the statements in?the fewest possible words.

How would you cope if you had a terminal illness? What if your son or daughter had no hope of ever having a normal life due to a life-threatening condition? Do these terminally sick people have the right to die?

In the UK, the question of assisted suicide or refusing medical treatment is extremely divisive(有分歧的); euthanasia is illegal in Britain, which is the act of helping a terminally-ill person to kill himself.

However, a 13-year-old English girl has won the right to refuse medical treatment this week after a hospital dropped a legal attempt to force her to have a heart transplant. Hannah Jones, who has spent eight years in and out of hospital battling heart problems, told child protection officers she wanted to die with dignity rather than face the operation and have to take constant medical treatment afterwards. Despite initial efforts by her local health authority to remove Hannah from her family and force her to undergo the transplant, legal and medical experts said that a child of her age was able to make an informed decision to refuse treatment.

Hannah’s decision to stop treatment and spend the rest of her life at home with her family was made entirely by herself, according to her father, who spoke of his admiration for her. "Hannah made that decision consciously on her own, a bit like a grown-up, even though she was only 12 at the time, and she has maintained that decision," said Andrew Jones.

The headmaster of Hannah’s school described her as intelligent and capable of making her own decisions. "Her presence is a source of inspiration to us all through the courage and dignity that she displays," he said.

(Note: Answer the questions or complete the statements in NO MORE THAN TEN WORDS.)

81. What is “euthanasia” (in paragraph 2)?

82. The hospital’s original plan for Hannah was to _____________________________________.

83. Hannah Jones prefers dying with dignity to ________________________________________.

84. What does the writer intend to discuss with the example of Hannah?