1 . A new study suggests that dark markings on the planet Mars represent sand — not water. The research in 2015 suggested that lines on some Martian hills were evidence of water. Yet American scientists now say these lines appear more like dry flows of sand. If water is present, it is likely to be a small amount. Water in liquid form would be necessary for microbial (微生物的) life.

NASA, the American space agency, said more research is needed. Michael Meyer is the lead scientist for NASA’s Mars exploration programme. He noted that the latest study does not reject the presence of water. But he admitted, “It just may not be as exciting as the idea of rivers going down the sides of cliffs (悬崖).”

The new findings come from a team led by Colin Dundas of the United States Geological Survey. His team measured 151 of these lines in 10 areas. Most of the lines end with slopes (倾斜) between 28 degrees and 35 degrees. These measurements are similar to active sand dunes (沙丘) on both Mars and Earth. A small covering of dust that moves and sometimes becomes lighter might help explain the markings. They usually appear in the Martian summertime, and then disappear until the next year. If these lines are dry, this suggests that recent Mars bas not had large amounts of liquid water. Dundas and his research team say that many questions remain.

“I still think that Mars has great potential for having had life early on in its history,” Meyer said. “As long as that’s true, we also have a reasonable possibility of life still being on Mars. It just happens to be cryptic or well hidden.”

NASA currently has no robotic — either on Mars or in development — with the ability to climb steep slopes. The lack of such equipment has engineers coming up with ideas like Martian helicopters or planes without pilots.

1. What do American scientists find on Mars now according to their study?

A．A lot of little life.	B．An amount of water.
C．Some Martian hills.	D．Dark markings are sand.

2. When do the markings come out?

A．In Martian spring.	B．In Martian summer.
C．In Martian autumn.	D．In Martian winter.

3. What’s Meyer’s opinion about having life on Mars?

A．Doubtful.

B．Trustful.

C．Unconcerned

D．Objective.

4. What does the underlined word “cryptic” in Paragraph 4 mean?

A．Undiscovered.

B．Strange.

C．Magical.

D．Icy.

4 . The famous scientist Stephen Hawking spoke at a science festival in Norway in 2017, “We are running out of space and the only places to go to are other worlds... Spreading out may be the only thing that saves us from ourselves. I’m convinced that humans need to leave Earth.”

Hawking was not alone in this view. Many experts feel that the only way for humanity to last far into the future is to colonize (移民于) other planets. That way, if a terrible disease, nuclear war or some other disaster strikes Earth, civilization as we know it would still have a chance. Mars is one of the most attractive destinations. NASA, the United Arab Emirates, the private company SpaceX, and the organization Mars One all have plans to send humans there. “Either we spread Earth to other planets, or we risk going extinct,” SpaceX founder Elon Musk said at a conference in 2013.

But not everyone agrees that colonizing Mars or any other planet is such a great plan. The most common argument against going is that it’s just too expensive or dangerous. It will take huge amounts of money and other resources just to get people there, let alone set up a place for them to live. It’s not even clear if humans could survive on Mars. One of the biggest dangers there is deadly radiation that ruins the planet.

Maybe all the time and money people would pour into a Mars mission would be better spent on more urgent projects here on Earth, like dealing with poverty or climate change. Some experts argue that handling a problem like an asteroid (小行星) strike or disease outbreak while staying here on Earth would be much easier and less expensive than surviving on a new planet.

In addition, moving to a new planet could harm or destroy anything that already lives there. Mars seems uninhabited, but it could possibly host micro-organism like. Human visitors may destroy this life or permanently change or damage the Martian environment. Some feel that’s too much of a risk to take.

1. Why did the author mention NASA, the United Arab Emirates, SpaceX and Mars One?

A．To stress the risk of dying out on Earth.

B．To provide evidence for Hawking’s theory.

C．To show growing intention of moving to Mars.

D．To explain the advanced technology in astronomy.

2. What can we learn from the passage?

A．Civilization is difficult to maintain on Earth.

B．It is costly and risky to colonize Mars.

C．Poverty is the most urgent problem to handle.

D．All the time and money should be spent on Earth.

3. What does the underlined word “uninhabited” mean in the last paragraph?

A．Not fit to live on.	B．Not steady to keep.
C．Not easy to approach.	D．Not safe to set foot on.

4. Which of the following can be the best title for the text?

A．Mars, Our Future Planet

B．Moving to A New Planet

C．Should We Colonize Mars?

D．Stay Home or Outer Space?

5 . Our fascination with Mars has never stopped. However, in the early days of space exploration, visits were restricted to “fly-bys”, such as those by Mariner Space Probes, by means of which craft would simply pass the planet, taking pictures and collecting data as they went. The Viking “orbiters” were next, and later craft in the Viking series, known as “Landers”, began to study the surface, equipped with instruments which continued to collect data about the environment until they stopped working.

The more recent “Rovers” move around the planet’s surface as they gather information. Current proposals include missions to study geographic features, climate, and soil components, in order to determine, among other things, whether the planet can ever have supported carbon-based life forms. Scientists now believe that at some stage the planet cooled dramatically, resulting in the near-loss of its atmosphere and, thanks to the wearing away of some surface features mineral deposits and other factors, it is also believed that liquid water once flowed here.

One of the most famous craft is “Phoenix”, which landed in November 2008. Its mission was to obtain samples from beneath the surface by digging into the arctic ice while its camera provided geological data and other equipment scanned the atmosphere, measuring temperature and pressure in an attempt to discover whether the chemicals necessary for life might exist beneath the surface. The craft was expected to send back data for three months, but managed to hold out for further two. An especially important part of the project was the need to keep absolute cleanliness of the equipment in order to ensure that any organic material collected was not contaminated by microbes(微生物).

In the future manned landings may probably come true-and though it may seem an extremely difficult undertaking, plans have already been discussed for the “terraforming(行星地球化)”of the planet, giving it an atmosphere, oceans and other elements similar to earth, with, the possibility of human settlement.

1. According to the text, what is “fly-by”?

A．A type of UFO.	B．A photograph of a planet.
C．A planet of the solar system.	D．A way of collecting information.

2. Which of the following is evidence of liquid water on Mars?

A．There is ice on it.

B．It once had some mineral deposits.

C．It once had carbon-based life forms.

D．There are some damaged areas on its surface.

3. What does the underlined word “contaminated” in Paragraph 3 mean?

A．Polluted.

B．Protected.

C．Controlled.

D．Reduced.

4. How does the author feel about human beings going Mars?

A．It will happen very soon.

B．It may be hard, but it’s possible.

C．It will be full of uncertainties, but it’s worth the efforts.

D．It relies on different countries working together.