The Yangtze River is the longest river in China and the third longest river in the world. It is just after the Nile in Africa and the Amazon in South America. It is about 6,380 kilometers long. It starts from the Tanggula Range and runs through many cities including Qinghai, Tibet, Sichuan, Yunnan, and so on. Finally it runs into the ocean in Shanghai.

During the long history of ancient China, this river helped feed millions of people and developed amazing cultures. The important cities such as Shanghai and Nanjing are sitting along the river.

However, the Yangtze River also faces some problems. In the past, the water in it was clean but now it is dirty. A lot of fish died because of water pollution. Luckily, people realized the importance of protecting the Yangtze River. A program was set up in 1989 to protect the water and land around the river. It was successful because it helped improve the environment. The other program is about endangered animals. It helps protect white-flag dolphins, one of the rarest animals in the world. The number of white-flag dolphins in China dropped because of the pollution in the Yangtze River.

So far, we’ve made some achievements. However, we still have a long way to go to protect the great river. Let’s work together to help our Mother River become as clean as it used to be.

Trees are useful to man in important ways: they provide him with wood and other products；they provide him shade；and they help to prevent droughts（旱灾）and floods.

Unfortunately，in many parts of the world，man has not realized that the third of these services is the most important. In his eagerness to make money from trees，（1）______________，only to find that without them he has lost the best friends he had.

This does not only mean that man will have fewer trees. The results are even more serious: for where there are trees，their roots break up soil allowing the rain to sink in and also bind（固定）the soil，thus preventing it from being washed away easily；but where there are no trees，the rain falls on hard ground and flows away，causing floods and carrying away the rich top-soil. When the top-soil is gone，nothing remains but worthless desert.

Two thousand years ago，a rich and powerful country cut down its trees to build warships，with which to gain itself and empire. It set up the empire，but without its trees，（2）_______________. When the empire fell to pieces，the home country found itself faced by floods and starvation（饥荒）.

Even though a government realizes the importance of a plentiful supply of trees，it is difficult for it to persuade（说服）the villager to see this. The villager wants wood to cook his food，and he can earn money by making charcoal or selling wood to the townsman. He is usually too lazy or too careless to plant and look after trees. So unless the government has a good system of control，or can educate the people，the forests will slowly disappear.

It’s very popular to travel in modern life. As travelers, we should try our best to protect the environment. Here is some advice on how to be a green traveler.

◆Make smarter flight choices

Air travel is not an environmentally-friendly way to travel because it uses a lot of energy. If you must fly, be sure to pack light to cut down the plane’s load. And try to book a non-stop fight(预订直达航班). Connecting fights(转机航班) usually require longer periods of flying and planes will use more energy.

◆Respect(尊重) natural environment

Marked hiking tails(有指示标识的游览步道) are there usually to protect the natural environment and keep wild plants safe. In beach areas, don’t use products that are harmful to the sea water and try to protect the ocean’s ecosystem.

◆Support locals directly

Buying handmade products and art pieces created by local people can help hand down cultural tradition and create jobs. Food that is grown locally and things that are sold by local families are often better and cheaper, all while helping keep money in local pockets.

◆Find ways to give back

Consider the ways that you can help the local community and give back while traveling. This can be as simple as picking up litter in a park or volunteering to clean up a beach. If you’re planning a trip where volunteering is your main goal, make sure you won’t take jobs away from local people.