Recent efforts toward the greening of our cities have achieved much, although the results are still far from satisfactory. In recent years many trees have been planted in the cities and much care has been taken of the planted trees. In spite of all this, the greening process is relatively slow compared with cities in many other countries. For example, the green space available on average to each Shanghai citizen is only 0.4 Mu while every Londoner has more than 20 Mu.

We can benefit much from making our cities greener by planting trees. First, trees absorb carbon dioxide to produce oxygen which is essential to the health of human beings. Second, trees and other greenery make our cities more beautiful. Third, trees can also improve the climate of the cities.

Since we can get so much from making our cities greener, we should spare no effort to do that. We should plant more trees and take better care of them. We also should not cut down the trees. In a word, we should do everything to add to the greening of our cities.

4. Saving animals

There is an undeniable fact that the number of animals is declining faster than ever before. According to a recent survey made by some experts, about 37 species disappear from our earth every year. It is obvious that the problem has become a serious one worth our concern.

When we explore this problem, some underlying factors emerge. In the very first place, human beings have played a big part. With the fast development of human society, the environment is much destroyed, and animals lose their home. Accordingly, some species become extinct. What’s more, people hunt animals for food and skin. A good case in point is that the Japanese have killed a lot of whales because they like to eat the meat. In addition, human beings are largely responsible for the pollution of natural environment, and poison animals in many ways.

The current problem, I believe, should be solved immediately. First of all, our government should play a key role in making relevant rules and protecting animals. The general public should also be educated to value the existence of these animals on our planet.

5.The Balance of Ecology

Man is part of nature. They can only survive if they live in harmony with nature. Otherwise the ecological balance will be broken and man has to pay for what he has done to his environment.

In its narrow sense, nature here refers to the natural environment around us including plants and animals. Trees can clean the air by absorbing harmful gases like carbon dioxide. Forests can maintain a good and stable climate, provide habitat for wild lives, and prevent sandy wind from passing people. Almost all the green plants can serve as specialists in beautifying nature and purifying air.

Animals are good friends for mankind. Owl, cat, snake can help us to eliminate some infectious diseases by killing mice. Even little insects play a very important role in bringing us a rich, musical and poetic world. Some like bee can make delectable honey; some have the same ability as birds’ to grasp injurious insects. Otherwise, the latter may eat as much grain as they like until farmers can harvest nothing from what they grow.

n short, every species has its reason for existing. Without them, the ecological system is destroyed and there will be no harmonious environment for man to live. People should learn to know the serious result.