As the backbone of the North American continent, ______is known as the Continental Divide

The Pennies is known as the backbone of England.（)

In some cities of North China, the noise pollution is as pronounced as that in Tokyo.A．con

The Backbone of North America refers to theA．Appalachian Mountains.B．Rocky Mountains.C．Cas

The national day of Canada is______as a commemoration of the passage of the British North

______is（are)considered as "the backbone of the continent" in America, and is（are) also kn

As the chief center of the American War of Independence,______was called "birthplace of Am