Mars is not it seems the dry old planet we once believed it to be. Astronauts who are【C1

Mars is not, it seems, the dry old planet we once believed it to be. Astronauts who are【C1】______to go there in the next decade may find plenty【C2】______water to slake(消除)their thirst.

And with water present the【C3】______of finding some sort of life on Mars are【C4】______brighter.

This is the view of 40【C5】______all over the world who have been analyzing【C6】______of pictures and other scientific【C7】______obtained by robot explorers in the sixties and seventies.

To begin with, scientists thought the Red Planet was as【C8】______as the Moon with dust storms swirling over vast sandy【C9】______. But now the picture is very different with mountains and valleys carved by【C10】______glaciers and torrential rivers rushing and rumbling deep underground.

In a report on the【C11】______of the Martian pictures Dr. Michael Car of the U.S. Geological Survey comments, "I am【C12】______there"s lots of water on Mars." Any surface water will be in the【C13】______of ice. But it could【C14】______explorers having to take so much fresh【C15】______with them.

The report says【C16】______Mars probably had a warmer climate in ages【C17】______due to its axis having been more steeply tilted towards the Sun.

【C18】______convincing signs of plant or animal life have been【C19】______by instruments soft. landed on Mars,【C20】______only the immediate vicinity of landing vehicles could be examined.

【C1】

A．expected

B．hoped

C．required

D．eager

请帮忙给出正确答案和分析，谢谢！