题目内容：

D

Mars was the first planet that humans attempted to get to. Since the 1960’s, scientists have been working to learn more information about the Mars’ past, We now know that Mars was once a warm, wet place with great oceans and deep rivers. We also know that about 3.7 billion years ago, all that water disappeared when the planet lost its air. But why did the atmosphere on Mars change so greatly?

NASA had launched the MAVEN spacecraft in the hope of answering that very question. MAVEN will study the remains of Mars’ air and help scientists figure out what became of the rest of it．

The spacecraft was launched on Monday, November 18, 2013, from Cape Canaveral, Florida. The trip to Mars takes about 10 months. and MAVEN is scheduled to go into orbit in September 2014. It is the first spacecraft created with the purpose of studying Mars’ atmosphere. Its wings measures 37.5 feet not quite the length of a school bus, and it weighs 1991 pounds about the same amount as a small car. MAVEN is equipped with eight different tools to measure and study the planet’s atmosphere. To collect information, it will fly in orbit as fast as 3278 miles per hour, and as slow as 93 miles per hour.

Once it arrived at Mars, MAVEN will have plenty of company. The spacecraft Curiosity is still walking around the planet’s rocky surface, studying the geology, chemistry and possible biology there. NASA currently has a number of spacecrafts getting unique views of Mars with powerful cameras and telescopes. These missions are all slow, steady steps forward to discover Mars secret past. While the results may not be revealed for some time, an exciting exploration is on the way.

1.We can learn from the first paragraph that________

A．all the scientists wanted to live on Mars

B．people have had a better knowledge of Mars nowadays

C．spaceships have been sent up to Mars since 1960s

D．all the water on Mars has been gone for ten billion years

2.The MAVEN spacecraft has been launched with the purpose of________

A．analyzing the change of the atmosphere on Mars

B．assisting Curiosity in studying the surface of Mars.

C. analyzing what is contained in Mars’ air

D．checking whether water still exists on Mars

3.It can be inferred from, the text that__________．

A．many different tasks will be given to MAVEN when it lands on Mars

B．many spacecrafts are working around Mars to study its water

C．more wonderful things about Mars will be found in the future

D．more spacecraft will be sent up to help Curiosity

4.What is the best title of this text?

A．A new finding on Mars

B．A new spacecraft sent to Mars

C．The rapid development of Mars

D．The great change of the Mars’ atmosphere