city-state	overcrowding	 urban sprawl	jet lag
factor	lighthouse	metro	index
1.	an independent state consisting of a city and the area around it	…………………..
2.	an underground train system	…………………..
3.	a system that shows the level of prices and wages, etc. so that	
	they can be compared with those of a previous date.	…………………..
4.	the feeling of tiredness and confusion after you fly between	
	places that have a time difference of several hours. 	…………………..
5.	a tower with a powerful flashing light that guides ships away from danger.  …………………..
6.	a fact or situation that influences the result of something	   …………………..
7.	the situation when there are too many people or things in one place	   …………………..
8.	the spread of a city into the area surrounding it, often without planning   …………………..