Frightening nature教案

reference for teaching
     i. 异国风情
1. the grand canyon
      the grand canyon (大峡谷) is considered one of the seven wonders of the natural
world. it is one of america's most famous national parks. visitors to the canyon come from all parts of the world. officials say about 5 million people visit the grand canyon each year.
      the canyon extends 450 kilometers. but the surrounding area does not suggest the existence of such a large opening in the earth. visitors come upon the canyon suddenly, when they reach the edge. then they are looking at a land like nothing else in the world. walls of rock fall away sharply. in some places，the canyon walls are more than a kilometer deep. far below is the dark, turning line of the colo 阅读全文