2 . Most people make tree houses using a pile of wood, a hammer, and some nails. Mitchell Joachim, an architect from the Massachusetts Institute of Technology, has a (n) _______ vision. He pictures a day when homes will be created from living trees.

Joachim’s vision _______ an idea called pleaching (编织), where tree branches are growing so that they _______ weave together. Since the growth patterns of trees are _______ by wind and sunlight, it may be _______ to control the way a tree develops.

These fabricated tree house habitats would use trees got into shape as housing. One of the _______ of these designs is that trees would not have to be cut down.

“A 100 percent tree house would take _______ to create,” Joachim said. Depending on the climate, a house could take anywhere from 5 to 30 years to grow. Fortunately, there’s a way to _______ the process. Joachim suggests including _______ materials such as the sod (草皮), grass and living branches in the housing designs. “This material would be able to move as the house grows,” Joachim said.

A home would become an actual ecosystem, a community of plants, animals, and bacteria working together. The trees would also give off water vapor that would assist in ________ the homes. Solar panels and wind would help provide ________. The tree homes might even have soil pockets, ________ plants could grow from the structure itself.

Work has already ________ on Joachim’s first design — a house made from 50 percent recycled materials and 50 percent living things. Joachim is confident about the ________ of his work, as he uses natural products ________ nature.

“The environment and its study are very important. We need to respect nature, don’t take it for granted,” he said.

3 . Mariah Reading is an environmentalist, who grew up with an early appreciation for nature. While studying art at Bowdoin College, she saw the vast amounts of _________ from her painting and sculpture classes. She began to seriously consider her footprint as a(n) _________. “How can I paint landscapes if I’m _________ them?” she thought. Then she started using the rubbish as her canvas (画布).

After graduation, Mariah travelled throughout the country, _________ rubbish to bring to her studio. One day, a _________ hubcap (轮毂盖) she found by the side of the road gave her a new _________ . She noticed the half hubcap had cracked off to _________ the line of the mountain range that she was in. So she _________ the mountain landscape on it and held it up in front of the real _________ and took a photo. It became the first in her __________ series.

Over the years, she has painted more than 100 pieces of rubbish and photographed her transformations __________ matching real-life landscapes. It’s like __________ new life into forgotten objects. Her practice __________ the principle of “leaving no trace” by __________ painting with sculpture and photography. Mariah hopes people see themselves and their own habits __________ into her works and make small changes in their everyday lives.

4 . Many cities around the world today are heavily polluted. Careless methods of production and ________ of consumer demands for environment friendly products have ________ the pollution problem. One ________ is that millions of tons of glass, paper, plastic, and metal containers are produced, and these are difficult to get rid of.

________, today, more and more consumers are choosing “green” and demanding that the products they buy should be safe for the environment. ________ they buy a product, they ask questions like these: “Will this shampoo damage the environment?” “Can this metal container be ________ or can it only be used once?”

A recent study showed that two ________ five adults now consider the environmental safety of a product before they buy it. This means that companies must now change the ________ they make and sell their products to make sure that they are “green,” that is, friendly to the environment.

Only a few years ago, it was impossible to find green products in supermarkets, but now there are hundreds. Some supermarket products ________ labels to show that the product is green. Some companies emphasize that their products are clean and safe in their advertising and have made it their main selling ________.

The ________ for a safer and cleaner environment is making companies rethink ________ they do business. No longer will the public accept the old ________ of “Buy it, use it, throw it away and forget it.” The public ________ is still here, and companies are ________ their act gradually.

5 . Life will be peaceful if you always do kind things. I teach my daughters to develop a habit of _____ others. The little acts of _____ give you opportunities to provide service for others. They can make you remember how great it feels to be kind and helpful.

We _____ in a rural (乡村的) area. Most of what we see is beautiful nature. One of the exceptions to the _____ is the rubbish that some people throw out of their car windows as they drive along the rural roads. One of the few _____ of living there is the lack of _____ public services, such as rubbish collection, which is common in the city.

A helping behavior that I practice regularly with my daughters is _____ rubbish in our neighborhood. My daughters often have a match to see who can collect the most rubbish. They will often say to me in a(n) _____ voice, “There’s some rubbish, Daddy—stop the car!” And if we have time, we will often get out of our car and pick it up. _____ it may seem strange, we do it. In fact, we enjoy it. We pick up rubbish in parks, on sidewalks, almost anywhere.

One day I saw a stranger picking up rubbish on the road. I stopped. He ______ his head and smiled, ”I saw you doing this with your family. It’s a good ______ to protect our environment.“

There are many other ways to ______ kindness for others. You may share a dinner with a beggar, visit ______ old people in the nursing home, or help the blind ______ the street. You can think of something that can be finished _______but helpful. It is fun, self-satisfying, and What’s more, it can set a good example. Helping others is helping yourself.

8 . Conservationists are breeding (饲养) lions in the Southern African nation of Zimbabwe. The wildlife experts hope to increase the lion population to keep the great cats from _______.

In some areas, lions and human beings are _______ control of land. Researchers believe something must be done quickly to _______ the animals.

The African Lion and Environmental Research Trust (ALERT) has more than 100 _______ in its breeding program. Antelope Park Farm is one of two sites ALERT operates in Zimbabwe.

Gary Jones heads the Antelope Park Farm. He says ALERT has become involved _______ a sharp drop in the number of lions. His group believes this has been _______ mainly by humans. There are more people moving to this area every year. The lions have _______ land on which to live.

Gary Jones says the decrease in the lion population affects the whole _______. He adds that other African nations are also seeing the _______ effects of this.

There are countries, ________ in central and north Africa, where the lion population has reached a(n) ________ level. Burundi, a country of east-central Africa, for instance, does not have lions in its national parks. It ________ wants to have lions reintroduced back into its national parks. The reason is that when you take the lion out of the equation (平衡), suddenly you get all ________ things to start happening with the balance of ________. For example, you get too many prey (猎物) species, like giraffes and zebras.

The United Nations’ Food and Agriculture Organization says wild animals are threatened when farmers try to ________ their plants or animals.

9 . I fell in love with Yosemite National Park the first time I saw it, when I was 13. My parents took us there for camping. On the way out, I asked them to wait while I ran up to E1 Capitan, a huge rock of 3,300 feet straight up. I touched that giant rock and knew ________ I wanted to climb it. That has been my life’s passion ever since —   ________ the rocks and mountains of Yosemite. I’ve long made Yosemite my ________.

About 15 years ago I started seeing a lot of _______, like toilet paper, beer cans, and empty boxes, around the area. It’s _______ me why visitors started respecting the place ________ and treated such a beautiful home-like place this way.

I tried _______ trash (垃圾) myself, but the job was too big. I would spend an hour or two on the job, only to find the area trashed all over again weeks later. Finally, I got so _______ it that I decided something had to change.

As a rock-climbing guide, I knew ________about organizing any big event. But in 2004, together with some climbers, I set a date for a cleanup. On that day, more than 300 people showed up. Over three days we collected about 6,000 pounds of trash. It was amazing how much we were able to ________. I couldn’t believe the ________ we made — the park looked clean!

Each year volunteers come for the cleanup from everywhere. In 2007 alone, 2,945 people picked up 42,330 pounds of trash and ________ 132 miles of roadway.

I often hear people ________ about their surroundings. If you are one of them, I would say the only way to change things is by doing rather than complaining. We need to teach by ________. You can’t blame others ________ you start with yourself.

10 . The Keeper of the River

An old man had been working for many years for a town. His job was to clear away natural waste from the pool water in the hills, which made up the lovely river flowing through the town nearby. Quietly and_______, the old man guarded the hills, removed the leaves and branches, and cleaned up the dirt that would have _______ and polluted the fresh flow of water. The town soon became a popular attraction for tourists. Elegant swans (天鹅) floated along the clear river and the view was so beautiful_______words.

Years passed. One evening the town committee met. As they reviewed the budget, one man’s eye caught sight of the salary figure being paid to the seldom seen keeper of the river. He asked, “Who is the old man? Why do we continue to employ him? No one in town ever see him. For all we know, the strange keeper of the hills isn’t doing his job. His position isn’t necessary any longer. ” Then they voted to _______ the man.

For several weeks, nothing changed……

By early autumn, the trees began to _______their leaves. Small branches broke off and fell into the pools of the hills,_______the flow of the shining water. One afternoon, someone noticed a slight yellowish-brown color in the river. A few days later, the water was much_______. Within another week, an oily something covered some sections of the water along the banks, and a terrible _______ was soon sensed. Swans left, and so did the tourists. The only thing that was now visiting the village was disease and sickness.

Quickly, the embarrassed town committee called a special meeting. Realising their huge error in_______, they rehired the old keeper of the river again, and within a few weeks, the river began to clear up. Swans and tourists came back again and new life returned to the small town in the Alps.

Never ignore the seeming smallness of a task, job, or life. They may all make a________.