How do I write an introductory paragraph on the impact of Olympic Games on an economy.

In order to write an introductory paragraph, you need to
know what you are going to argue.  You should not write your introductory paragraph
until you have a good idea of the overall thrust of your
paper.

On this topic, there are studies that argue both
sides and you will need to decide what you believe.  Some studies argue that hosting the
games has a positive impact on a nation's economy.  The argument is that the games
attract so much tourism that they have a net beneficial
impact.

On the other hand, there are studies that argue
that Olympic Games do not really help a country's economy.  Some studies argue that all
the construction that is needed in order to host the games ends up costing more than the
games are worth.  The money is often spent on large sporting venues that never get used
again.  This waste negates the positive impacts on
tourism.

So, in order to write your introduction, you need
to decide which side you are going to take and then write a paragraph that briefly
states this and also states the bare bones of what your argument will
be.