Scientists have found what look like caves on Mars, and say they could be protec

Scientists have found what look like caves onMars, and say they could be protecting life from the planet’s terribleenvironment.

The first caves appear as seven mysteriousblack dots （点） on thepictures which were sent back by NASA’s Mars Odyssey orbiter. Each as large asa football field, they may be openings into natural caves below the Martian surface.

“If there is life on Mars, there is a goodchance that you’d find it in caves,” said Jut Wynne, one of the researchers whonoticed the features (特征)while working on a US Geological Survey Mars Cave Detection Program.

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

One photo taken at night by an infraredimager(红外线成像器) showed onehole to be unusually warm, suggesting hot air may be flowing out.

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

He agreed such caves could be perfect placesto search for life escaping from the bitterly cold, radiation-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 wholerange of bacteria (细菌). Acave is also a protection from radiation; the surface of Mars is exposed tohigh levels of space radiation.”

The caves probably formed when tube-shapedlava flows(管状岩浆流) spreadacross the planet long ago. The outside of the tubes cooled, forming solidwalls, while something hotter inside allowed the remaining to flow out, formingcaves.

1. Whatdoes the passage mainly talk about?

A. How the caves were formed on Mars.

B. How NASA sent the pictures back to earth

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

D. Scientists have completely recognized the surface ofMars.

2. We canlearn 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-soakedand dry

3.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 search for life

D. There would be life on Mars.

4.Necessary conditions for life on Mars mentioned in the passage mayinclude_________.

A. lava andenergy          B. water andradiation from space

C. gases andlava           D. water andprotection from radiation

5. whatdoes the underlined word “ the planet” in paragraph 1 refer to?

A. the Mars     B. theearth      C. thecaves       D. radiation

试题答案

【答案】

1.C2.D3.B4.D5.A

【解析】略