1 . Many people know that rubbish is a big problem on the Earth. What many people don’t know is that rubbish is becoming a problem in outer space too. Years of space exploration (探索) have left tons of “space junk” (太空垃圾) around the planet.
According to the reports of BBC, there are more than 22,000 pieces of rubbish in space around the Earth. And these are just the objects that are easy to see. There may be millions of smaller pieces of rubbish that we can’t see.
The pieces of space junk move around the planet at very high speeds. They move so fast that even a very small piece can become dangerous. If they crashed (碰撞) into each other, it could cause explosions that might even hurt people on the Earth. If the tiniest piece of rubbish crashed into a space shuttle (航天飞机), it could blow open a hole as big as an elephant.
To help solve this problem, countries around the world have agreed to limit the time their space tools stay in space to 25 years. Each tool must fall safely into the Earth’s atmosphere, or upper parts of the sky. There, it will burn up, and it won’t crash near the Earth.
1. What is becoming a problem in outer space?| A．Unseen things. | B．Many big holes. |
| C．Too much space junk. | D．A lot of explosions. |
| A．It may kill elephants. |
| B．It causes air pollution. |
| C．It moves faster than space shuttles. |
| D．It may cause explosions and hurt people. |
| A．Burn them on the Earth. | B．Limit their time in space. |
| C．Let them crash in the sky. | D．Make them move slowly. |
2 . The truest explanation of recycling involves taking a material, melting(融化) it down, and turning it back into itself over and over. This can be done with glass and metal, which can both be remelted and reformed into bottles or cans forever. This is a closed-loop(闭环) system, so it’s very desirable. On the other hand, some materials slowly degrade(降解) over time, meaning they can be reformed maybe once or twice, but after a while the chemical composition of the original substance has changed and it can no longer be turned back into what it once was. This is called downcycling(降级回收).
The downcycling of plastic is one of the serious issues surrounding this material. For example, plastic water or soda bottles are seldom turned back into bottles. The other is the fact that plastic never biodegrades(生物降解). Many materials newspaper included, will biodegrade at the end of their lives. When paper enters the environment, given exposure to the air, it breaks down, leaving the world undamaged. Plastic, on the other hand, photodegrades(光降解), and this is very concerning. As discussed earlier, in the process of photodegrading, wind, sun, and water break plastic down into smaller and smaller particles(颗粒) that will cause great damage to the ocean ecosystem.
Finally, there is concern about heating food in plastic containers. Avoid reheating food in plastic containers in the microwave, and stop covering food with plastic wrap. Storing cool food in plastic containers isn’t as big a concern, but avoid heating food and plastic together to eliminate the possibility of plastic into your food.
So the disadvantages to plastic are that it can’t really be recycled in the true meaning of the term, it will never disappear from our environment because it can’t biodegrade, and it is a vehicle to deliver dangerous chemicals into our food chains.
1. What is a satisfying recycling system?| A．It’s easy to find alternative metals. | B．Its process is an open-loop system. |
| C．Materials can be reused over and again. | D．Composition of materials can be changed. |
| A．The threat to oceans. | B．The impact on foods. |
| C．The process of breaking down. | D．The pollution of the atmosphere. |
| A．Assess. | B．Remove. | C．Weight. | D．Reduce. |
| A．Positive. | B．Indifferent. | C．Negative. | D．Unclear. |
