提纲：
1、The world we live in is becoming more and more intolerable because of environmental destruction.
2、A lot of measures have been taken …
3、However, the problem of environmental protection remains far from being solved.
【参考范文】
The world we live in is becoming more and more intolerable because of environmental destruction. For example , forest destruction results in decrease of planting land and unpleasant weather. In addition, man is faced with problems of water pollution and air pollution.
A lot of measures have been taken. Planting trees helps improve and beautify the environment. Besides, laws concerning environmental protection have been put into effect and achieved good results.
However, the problem of environmental protection remains far from being solved. On the one hand, the environment pollution and destruction are getting worse and worse in the modern world. On the other hand, the lack of knowledge about the importance of protecting environment hinders the solving of the problem. In a word, there is a long way to go before we enjoy a clean and comfortable world.