仿照例子写一篇关于加拿大的问答。
A：Here is the map of the U．S.
B：I know about the U．S.
A：What's the capital city of the U．S.?
B：Washington，D.C. is the capital city of the U．S.
A：What do they speak in the U．S.?
B：They speak English.
A：What colour is the flag of the U．S.?
B：The flag of the U．S. is red，white and blue.
