标签：话题作文 话题 英语六级作文
字数：3000字
提要：英语六级作文题及范文 1989年1月六级作文题及范文 Directions:The Problem of Human Population 范文： It has been estimated that a thousand years ago there were less than 400 million people on earth. However, in the recent thousand years human population has increased nearly 20 times. Nowadays the world population has reached more than 7000 million. The population explosion has caused many problem..