托福听力背景积累：尼亚加拉瀑布

尼亚加拉瀑布(Niagara Falls)位于加拿大和美国交界的尼亚加拉河中段地区，有着世界七大奇景之一的美誉。尼亚加拉瀑布其实不是一个瀑布。有人说它由两个瀑布组成，“加拿大瀑布”和“美国瀑布”--加拿大人多半这么说;如照美国人的说法，则是3个瀑布：“马蹄瀑布”(Horseshoe Falls，就是“加拿大瀑布”，它状如马蹄)、“美国瀑布”(American Falls)和“新娘面纱瀑布”(Bridal Veil Falls)。“新娘面纱”在宽阔的“美国瀑布”旁边，尽管只细细一缕，却自成一支，所以美国人“宣告”了它的“独立”。 尼亚加拉的三条瀑布流面宽达1160米(如果加上两个岛屿，宽可达1240米)，虽然分成三股，却是同一水源，同一归宿--尼亚加拉河。

Niagara Falls comprises three distinct cataracts. The tallest are the American and Bridal Veil falls on the American side, separated by tiny Luna Island and plunging over jagged rocks in a 180ft drop; the broad Horseshoe Falls which curve their way over to Canada are probably the most impressive. They date back a mere twelve thousand years, when the retreat of melting glaciers allowed water trapped in Lake Erie to gush north to Lake Ontario. Back then the falls were seven miles downriver, but constant erosion has cut them back to their present site. The falls are colorfully lit up at night, and many say they're most beautiful in winter, when the grounds are covered in snow and the waters turn to ice.

The best views on the American side are from the Prospect Point Observation Tower (daily; 50￠), and from the area at its base where the water rushes past; Terrapin Point on Goat Island in the middle of the river has similar views of Horseshoe Falls. The nineteenth-century tightrope-walker Blondin crossed the Niagara repeatedly near here, and even carried passengers across on his back; other suicidal fools over the years have taken the plunge in barrels. One survivor among the many fatalities was the Englishman Bobby Leach, who went over in a steel barrel in July 1911 and had to spend the rest of the year in hospital. That practice has since been banned (though a couple of maniacs did it in summer 1995 and came away with minor bruises), for reasons which become self-evident when you approach the towering cascade on the not-to-be-missed Maid of the Mist boat trip from the foot of the observation tower (summer Mon-Fri 10am-5pm, Sat & Sun 10am-6pm; $8.50; 716/284-4233).

以上就是托福听力背景积累：尼亚加拉瀑布，大家可以整理其中的陌生词汇及句型，以及相关的历史知识，在托福听力考场上遇到此类问题的时候，你一定会感到惊喜。