answer: #Person1# says #Person1# is told that people in developed countries tend to leave big cities. But #Person2# tells #Person1# that in developing countries, people still move to big cities from the countryside for various reasons. This also causes many difficulties.
documents: #Person1#: In Britain, we are often told that people are leaving the big cities to live in the countryside, but is this the same worldwide?
  #Person2#: Not at all. If you look at the biggest cities in one thousand nine hundred and fifty, 7 out of the top 10 were in the developed countries. But by the year two thousand, the developing countries will have 8 out of top 10. New York, which in one thousand nine hundred and fifty, was number one with a population of around 12,000,000 will only be the sixth the largest city in the world, but with an extra 2 million.
  #Person1#: And London?
  #Person2#: London, which was number 2, won't even be in the top ten, its population in one thousand nine hundred and fifty, by the way, was about 10,000,000.
  #Person1#: And why is this happening? Why are people moving to the big cities from the country in the developing countries?
  #Person2#: The reasons are various, but many are moving to look for work and the problems caused by this are enormous. It said the 26,000,000 people will be living in Mexico City by the year two thousand, with Sao Paulo in Brazil, not far behind.
  #Person1#: It's hard to believe.
  #Person2#: I know. Well, just imagine the difficulties this is going to cause in terms of health, transport, an education.