how to make new form in Window phone 7

Dear everyone,
I am working on Project with window phone 7.
And i am wonder how to make a new form as we make new form in window form.
In window form, we have:

form1  a=new form1(); 
a.show();

But in window phone 7, Could we do it???
if someone know, please teach me.
Thank alot.

Tags: C#, Mobile Apps, Phone