I am a girl.
=I'm a girl.那you are ten years old.和 it isa book. 和my name is gina. 和thatisnot his shool.You are ten years old. =You're ten years old.It is a book. =It's a book.My name is Gina. (无可缩略的词) That is not his shool.=That isn't his shool.