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 colorado river(科罗拉多河). on the other side of the canyon, sunshine lights up the rock walls in red, orange and gold. the bright colors are the result of minerals in the rocks.
their appearance changes with the light, the time of years and the weather. at sunset, when the sun has moved across the sky, the canyon walls take on quieter colors of blue, purple(紫色) and green. hundreds of rocky points rise from the bottom of the canyon. some are very tall. yet all are below the level of an observer on the edge, looking over.
there are several ways to see the grand canyon．many visitors walk along paths
down into t he canyon. it takes several hours to walk to the bottom, it takes two times as long to walk back up．some visitors ride mules(骡子)t0 the bottom of the canyon and back．mules are strong animals that look like horses．they are known for their ability to walk slowly and safely on the paths．many people see the grand canyon by air．they pay a helicopter or airplane pilot to fly them above and around the canyon．others see it from the colorado river．they ride boats over the fast moving water．these trips can last from one week to three weeks．
america"s national park service is in charge of protecting the grand canyon from
the effects of so many visitors．visitors must carry a11 waste materials out of the area．all rocks．historical objects，plants and wildlife must be left untouched．the national park service tells its visitors，“take only photographs．leave only footprints．”
2．the birth of an island
surtsey was born in 1963．it was a great event for scientists．they were lucky enough to see the birth of this volcanic island．it began at 7：30 a．m．on 14th november．a fishing boat was sailing near iceland．the boat moved under the captain"s feet．he noticed a strange smell．he saw some black smoke．a volcano was erupting．the bottom of the grey atlantic was open．red—hot rocks，flames and smoke were rushing up from a split in the sea-bed．the island grew quickly．it was 10 metres high the next day and 60 metres high on 18th november．scientists flew to reykjavik to watch．it was very exciting．smoke and flames were still rushing up．pieces of red—hot rock were flying into the air and falling into the sea．the sea was boiling and there was a strange light in the sky. surtsey grew and grew．then it stopped in june 1967．it was 175 metres high and 2 kilometres long．and life was already coming to surtsey．
