题目要求：1. 近年来越来越多的民工涌入大城市

2. 产生这一社会现象的原因

参考范文：

For a number of years, there has been a steady rise in the number of rural laborers who flood into big cities. Many men work on construction sites, while many women work as dishwashers in restaurants or babysitters for city dwellers. Three reasons, in my mind, can account for this social phenomenon.

First and foremost, the limited land can no longer produce enough crops for an ever-increasing rural population. In the second place, there are far more opportunities in big cities—rural laborers dream of earning money through hard work. Last but by no means least, many of them want to live permanently in big cities, because they admire the way of living there, and wish their children to receive good education.

I firmly believe that if we try our best to create a healthy social atmosphere, rural laborers will make greater contribution to our nation.