阅读以下教材原句，仔细观察加颜色部分并补全空格。 1.The thought that they could cross the whole continent was exciting. 2.Some people have the idea that you can cross Canada in less than five days，but they forget the fact that Canada is 5,500 kilometres from coast to coast. 3.The girls were surprised at the fact that ocean ships can sail up the Great Lakes.