1.Have you visited Niagara Falls?
2.We can see Niagara Falls all at once at altitude.
3.The seven-mile-long gorge is merely the track of the falls as they move along.
4.Niagara Falls has become a tired old tourist sight.
5.The Grand canyon is truly masterpiece.
6.The"Great lakes", that is to say, the five large fresh-water lakes in central of Canada and America are like inland seas.
7.Can you believe that this canyon is two billion years old?
8.Those mesas are spectacular!
9.The west of Canada are the famous Rocky Mountains. In the east, mountains stretch down the coast of Canada, too.