题目内容：

For centuries, humans have wondered whether there is life on Mars. Why is Mars losing its air? Last week, the question was answered.

“The answer, is blowing in the wind,” said Michael Meyer. He is the lead scientist for Mars Exploration Program.

It turns out solar winds from the sun are slowly stripping( 除掉) away Mars' air. That is what scientists explained at a press conference.

Bruce Jakosky is the principal investigator on the MAVEN team. It is a spacecraft that collects information from Mars as it circles around the planet.

Today, Mars has a thin atmosphere. It is cold and dry. ______

"When we look at ancient Mars, we see a different type of surface. One that had valleys that looked like they were carved by water, lakes that were standing for a long period of time. We see an environment that was much more able to support liquid water."

Recently scientists found a kind of liquid water that flows with salt down a mountain area of the planet. But, it is not always there. Scientists already knew that ice exists on Mars. So why is it important to find liquid water?

"It means that we have a resource. And when we're looking at sending humans to Mars, water is one of the key things that we need to have. Not only for the astronauts to drink, but also to make oxygen and fuel."

Sending humans to Mars will be in the 2030s. Those chosen might fly any number of space vehicles still in development.

Human beings are developing rockets and spacecraft to get people to Mars. Scientists want to know how the human body reacts to being in space for long period of time.

Whether there is life on Mars remains unanswered. But some scientists think there might be some kind of microbial life on the planet. Finding life on another planet would change the way we view the whole universe.

1.What was the surface of ancient Mars like?

A. It had thin air. B. It was dry.

C. It had valleys that looked like they were carved by water. D. It had no water.

2.Which statement is TRUE according to the passage?

A. The surface of the Mars is different from it used to be.

B. Scientists have known whether there is life on Mars.

C. People can not send humans to Mars forever.

D. There is not any atmosphere on Mars.

3.What does the underlined word "Those" in the text refer to?

A. Scientists B. Rockets C. Astronauts D. Vehicles

4.Which of the following is the best for“______”in Paragraph 5?

A. But it used to be much different. B. It was the same case in the past.

C. It's always like this. D. It will be different in the future.