C

       Scientists have found what look like caves on Mars(火星), and say they could be protecting life from the planet’s terrible environment.

The first caves discovered beyond the Earth appear as seven anysterious black dots on the pictures sent back by NASA’s Mars Odyssey orbiter. Each as large as a football field, they may be openings into natural caves below the Martian suface.

“If there is life on Mars, there is a good chance you’d find it in caves,” said Jut Wynne,one of the reseachers who noticed the features while working on a US Geological Survey Mars Cave Detection Program.

Jonathan Clarke, a geologist with the Mars Society of Australia, yesterday described the discovery as exciting.

One photo taken at night by an infrared imager(红外线成像器) showed one hole to be unusualy warm, suggesting hot air trapped during the day is flowing out.

“I said:‘Wow, that’s a cave’” Dr. Clarke said excitedly. “People have been looking for these for a long time; now we have found them.”

He agreed such caves would be perfect places to hunt for life escaping from the bitterly cold,radiatiion-soaked(充满辐射的), dry surface.

“Tiny drops of water could collect inside,” he said. “If there are gases coming out, they could provide energy for a whole range of bacteria. A cave is also a protection from radiation; the surface of Mars is exposed to high levels of space radiation.”

The caves probably formed when tube-shaped lave flows(管状岩浆流) spread across the planet long ago. The outside of the tubes cooled, forming solid walls, while something hotter inside allowed the remaining have to flow out, forming caves.

64.What does the passage mainly talk about?

A.How the caves were formed on Mars.

B.How scientists found these caves on Mars.

C.Caves on Mars may be full of hot air or a sign of life.

D.Scientiste have completely recognized the surface of Mars.

65.We can learn from the passage that           .

A.water has already been found on Mars

B.the scientists found all the caves at night

C.it is certain that there is life in these caves

D.the surface of Mars is bitterly cold, radiation-soaked and dry

66.According to the passage, Dr. Clarke was so excited because        .

A.such caves could provide energy for life

B.they had finally found the caves on Mars

C.such caves would be perfect places to hunt for life

D.scientists had long been looking for these caves

67.Necessary conditions for life on Mars mentioned in the passage may include        .

A.lava and energy

B.water and radiation from space

C.gases and lava

D.water and protection from radiation

D

68.The best title of the 3^nl advertisement would be         

A.Training at Home                                       B.Learning at Home

C.Recording Work                                               D.Working at Home

69.According to the information above, if your child has hearing problems, you can turn to      .

A.At-Home Profession Corp.                               B.Globe Insurance Company

C.Bradford Pubbcations                                      D.American Inventors Corp.

70.From the advertisements above, we can learn that          .

A.Globe Insurance Company has a history of 51 years

B.as a medical transcriptionist, you may earn $ 25,000 a month

C.Bradford Pulications offers a treatment to hearing impaired parents

D.you can visit www. aic. com when you invent a new model of hearing aid

E

       Dogs wag(摇摆) their tails in different directions depending on whether they are excited and wanting to move forward or threatened and thinking of moving back, a study has found.

       Researchers in Italy  examined the tail wagging behaviour of 30 dogs, catching their responses to a range of stimuli(刺激物) with video camems. To conduct the study they chose 15 male dogs and 15 female ones aged between one and six years. The dogs were all family pets whose owners had allowed them to take part in the experiment at Bari Umversity. The dogs were placed in a large wooden box with an opening at the front to allow for them to view various stimuli. They were tested one at a time.

       The researchers led by Professor Giorgio Vallortigara of the University of Trieste found that when the dogs were shown their owners—a positive expenence—their tails wagged energetically to the right side. When they were shown an unfamiliar human they wagged to the right, but with somewhat less enthusiasm. The appears of a cat again caused a right-hand side wag, although with less intensity again. The appearance of a large unfamiliar dog, similar to a German shepherd, changed the direction of tail wagging to the left. Research ers supposed the dog was thinking of moving back. When the dogs were not shown any stimuli they tended to wag their tails to the left, suggesting they preferred company. While the changes in the tail wagging were not easily noticed without the aid of video, it was thought that the findings could help people judge the mood (心情) of dogs. Computer and video systems, for example, could be used by professional dog trainers to determine the mood of dogs that they were required to approach.

71.The video cameras were used to catch the dogs’ responses because      .

A.it was easier to catch the dogs’response changes in the tail wagging

B.the dogs were put in the wooden boxes and tested one at a time.

C.they enabled the dogs’owners to know about their dogs’habit

D.the dogs wagged their tails in different directions when they were in different moods

72.The underlined word“intensity” in the passage means        .

A.surprise                   B.worry                       C.excitement                     D.interest

73.When there are no stimuli, a dog will         .

A.wag to the left                                            B.wag to the right

C.not wag at all                                             D.wag to the left and then to the right

74.The underlined word “they” refers to         .

A.the dogs                  B.the trainers                    C.the systems                  D.the rescarchers

75.The purpose of doing the experiment is         .

A.to train dogs for their owners                            B.to help people judge the mood of dogs

C.to help dogs find company                               D.to help people choose their pet dogs

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