B
Many people know that rubbish is a big problem on the earth. What many people don’t know is that junk(垃圾)has become a problem in outer space too.
According to BBC News,there are more than 22,000 pieces of space junk floating around the earth. And
these are just the things that we can see from the surface of the earth by telescopes(望远镜). There are also millions of smaller pieces of junk that we can’t see.
Objects(物体),like bits of old space rockets or satellites,move around the planet at very high speeds. They are so fast that even a very small piece can break important satellites or become a danger to astronauts. If the tiniest piece of junk crashes into a spaceship,it can damage the spaceship.
To make things worse,when two objects in space crash,they will break into many smaller pieces. For example,when a US satellite hit an old Russian satellite in 2009,they broke into thousands of pieces,increasing the amount of space junk.
To reduce additional space junk,countries have agreed that all new space tools can only stay in space for 25 years at most. Each tool must be built to fall safely into the earth’s atmosphere(大气层)after that time. In the upper parts of the atmosphere,it will burn up.
Many scientists are also suggesting different ways to clean up space junk. In the UK,scientists are testing a metal net that can be fired into space junk. The net catches the junk and then pulls it into the earth’s atmosphere to burn up. The Germans are building robots that can collect pieces of space junk and bring them back to the earth to be safely destroyed.
“The problem is becoming more challenging because we’re sending more objects into space to help people use their mobile phones and computers,” says Marco Castronuovo,an Italian space researcher.
“It’s time to act now. The longer we leave the problem,the bigger it will become,” he says.
(
C
)4. What does the underlined word “these” in Paragraph 2 refer to?
A. Telescopes.
B. Satellites.
C. Pieces of space junk.
D. BBC News reports.
(
D
)5. Why is space junk considered a problem?
A. Because it burns up after it enters the atmosphere.
B. Because it often blocks the view of the telescopes on the earth.
C. Because it can force(迫使)new space tools to travel at slower speeds.
D. Because it may crash into other space tools causing damage or death.
(
B
)6. Countries want future space tools to be able to fall back into the earth’s atmosphere so that ______.
A. the tools can be reused later
B. the tools won’t become space junk
C. the earth’s atmosphere can stay clean
D. the effects of the space flight can be studied
(
B
)7. How do the Germans plan to deal with space junk?
A. Catch it with nets.
B. Use robots to collect it.
C. Burn it in the earth’s atmosphere.
D. Send it further away from the earth.
