3 . Space is where our future is — trips to the Moon, Mars and beyond. Most people would think that apart from comets (彗星) and stars, there is little else out there.     1     Scientists are now concerned that if we don’t clean it up, we may all be in great danger.

The first piece of space junk was created in the year of 1964, when the American satellite Vanguard I stopped operating.    2     However, since it kept orbiting around the Earth without any results, scientists became increasingly comfortable abandoning things that no longer served any useful purpose in space.

    3     The junk varies from tiny pieces of paint chipped off rockets to cameras, huge fuel tanks, and even odd items like the million-dollar tool kit that astronaut Heidemarie Stefanyshyn Piper lost during a spacewalk.

The major problem with the space trash is that it may hit working satellites and damage travelling spaceship. In addition to this, many pieces of junk may crash with each other and break into pieces which fall back to the Earth.     4     Ground stations have been built to monitor larger pieces of space trash to prevent them from crashing into working satellites or space shuttles.     5     They will stop littering in space and to clean up the trash already there.

4 . Some of the greatest problems we face today are concerned with the gradual destruction (破坏) of our environment through overuse of our _________. So my family do what we can. We take cloth bags to stores instead of using plastic bags. We walk where we don’t have to _________.

But when I’m the only one with a cloth bag in line at the grocery store, I ask myself: Does it do any good?

I recently found the answer from flamingos (火烈鸟). These beautiful birds gather in _________ groups of a thousand or more. Every year, when the time comes for migration (迁徙), a few flamingos start the process by _________ from the lake. But _________ of the others seem to notice, so the tiny group returns.

However, the next day they _________ again. This time a few more struggle along with them, but the vast majority _________ no attention, so these pioneers come back.

The trend continues for several more days. Every time a few more birds join in but, _________ the thousands of others still take no notice, the great migration plan is once again _________.

Then one day, things __________. The same small group of birds takes wing and a tiny number more join in, just as before. This time their total number is enough to tip the balance (扭转局势). As one, the whole group takes flight and the migration __________.

A few can make a __________. It’s true that all of the great problems of the world have been solved because of the __________ efforts of a few.

If you believe in a cause (事业), don’t __________. Others will someday notice and __________ we will solve even our greatest problems.

5 . Universities are doing everything they can to become a green campus. But there are also items students can do to make your campus more eco-friendly.

Recycle everything, especially paper!

There is a large amount of paper a college student goes through every term.     1     We know that these things can’t be avoided, but the way you handle the use of all the paper can really help create a better green campus.

Buy green.

    2     Paper, cleaning products and water are products that can be bought as recycled goods. They’re slightly more expensive than the normal products, but they’re worth buying to make a green campus.

Walk and bike to school.

Most campuses, especially those that are trying to become a more eco-friendly campus,have pretty good public transit (公共交通系统).     3     Walking or biking will help make your campus a green university.

    4    

A water bottle can be refilled at any water fountain and can easily be drunk in class or while riding a bike. This will protect the environment by decreasing the amount of plastic waste on your campus.

Buy used clothing.

It is usually thought of as something to do to save money.     5     Recycling clothes minimizes the amount of resources to make clothing and puts a dent in the problem of worldwide sweatshops.

With the development of science and technology, our life is becoming much better and more convenient. However, more garbage and pollution    1    (produce) at the same time, which    2    (lay) a heavy burden on our environment.    3    is known to all, environment plays a vital role in our daily life. In response to the severe situation, we should take effective    4    (measure) to protect the planet where we coexist. It is suggested that we should sort waste    5    (relieve) the situation.

Garbage classification, which is a good way to protect our environment, can’t be overemphasized. It can help separate recyclable waste, which can be    6    (full) used to help save the resources    7    a large degree. Not only can we make our environment clean and beautiful, but also recyclable waste can be made good use of to benefit us in return.

As garbage classification is significant, we should take    8    active part in putting it into practice. It’s a must for    9    (we) to learn to sort waste. It is the little things we do today that have a profound influence on the planet. Only if all of us make joint efforts can we make a big    10    (different) and have a good environment.

9 . In our modern world, when something wears out, we throw it away and buy a new one. The _________   is that countries around the world have growing mountains of _________ because people are throwing out more rubbish than ever before.

How did we become a throwaway society? First of all, it is now easier to_________ an object than to spend time and money to repair it. Thanks to modern manufacturing (制造业) and technology, companies are able to produce products quickly and inexpensively. Products are plentiful and _________.

Another cause is our_________ of disposable (一次性的) products. As _________ people, we are always looking for ways to save time and make our lives easier. Companies _________ thousands of different kinds of disposable products: paper plates, plastic cups, and cameras, to name a few.

Our appetite for new products also_________ to the problem. We are addicted to buying new things. Advertisements persuade us that _________ is better and that we will be happier with the latest products. The result is that we __________ useful possessions to make room for new ones.

All around the world, we can see the__________ of this throwaway lifestyle. Mountains of rubbish just keep getting bigger. To __________ the amount of rubbish and to protect the __________, more governments are requiring people to recycle materials. __________, this is not enough to solve our problem.

Maybe there is another way out. We need to repair our possessions instead of throwing them away. We also need to rethink our attitudes about__________. Repairing our possessions and changing our spending habits may be the best way to reduce the amount of rubbish and take care of our environment.