Many people are optimistic about the twenty first century and see it as an opportunity to make positive changes in the world.(注意：这句话照抄了原题，考试时这样做会被扣分的!) Given(作介词，表示“考虑到”) current trends however this optimism is certainly unwarranted. If we are to see our way safely into the twenty second century, many fundamental changes still need to be made.
The world has been changed in the twenty first century; advancements in medicine and technology have changed life and lifestyles for virtually all of the peoples of the world. Not only have these advancements brought society forward, it has brought society onto the cusp of a new era(新纪元的开始), the entire direction of human development is now changing from that of single nations eking out an existence(很好的短语，表示“勉强维持生活”)in some corner of the world, to the people of the world drawing together(团结起来) to take on projects and research that could never be accomplished in isolation.
These changes however, have not all been positive. The environmental impact of industrialization has changed the face of the world as well, polluting oceans and rivers, stripping (剥夺)the world of some of its oldest and most verdant forests (绿色森林)darkening the sky with air pollution, poking holes in the protective ozone layer, and leading to the development of radioactive poisons(放射型毒物) capable of poisoning the earth and continuing to poison it for millions of years to come. Meanwhile, man is beset by(被困扰) problems of overpopulation and pollution. Like vermin, man is being overcome by his own filth and inability to stop reproducing.
Man’s development in the last century has been massive, but in both directions, both forward and backward. This combination of development and destruction seems to be the basic nature of man, but if we are to survive, we must realize that progress, at the cost of ourselves is not only unacceptable but the path to destruction.
