Can i be a citizen of three countries?

It is possible to be a citizen of two or more countries depending on the counties laws they have set. Some allow it but others don't actually my mother told me she hasent gave up her citizenship to mexico to become a citizen in U.S.A because you have to resume that your american not mexican and she rather stay as a resident also lol she dosent want to take that test you have to take to become a citizen full of questions on U.S. history. If you want to know more and in good details heres a link you can go to:http://www.usimmigrationsupport.org/dual_citizenship.html