关于这篇文章的阅读理解

关于这篇文章的阅读理解
New York,London,Paris and other big citys are exciting places to live in.There are many interesting things to see ahd to do.
But there are serious problems in big cities too.It is expensive to live there,and there are too many people.Every year many people move to the cities to find work,study at good schools and receive high-quality medical care.But sometimes these people can not find work or good places to live .Also it is hard to keep big cities safe and clean.
So,before people move to a big city,they should think about the problems they might have to deal with there.