张汉熙高级英语第三版第一册Lesson 1 .ppt

Lesson 1 Face to Face with Hurricane Camille;Teaching Aims;Teaching Contents;;Warming-up Activities;; ;;;;;;;I. Background Knowledge;I. Background Knowledge; Incipient ([in'sipi?nt]初期的) hurricanes usually form over the tropical N Atlantic Ocean and mature as they drift westward. Hurricanes also occasionally form off the west coast of Mexico and move northeastward from that area. An average of 3. 5 tropical storms per year eventually mature into hurricanes along the east coast of North America, usually over the Caribbean Sea or Gulf of Mexico. ;2. Typhoon/cyclone: Similar storms occurring over the West Pacific Ocean and China Seas are called typhoons. Those over the Indian Ocean are called tropical cyclones (旋风). Tornado: a localized and violently destructive windstorm occurring over land characterized by a funnel-shaped cloud extending toward the ground 一般只指开阔”陆地上“形成的”龙卷风“，规模一般比hurricane 小。 ;A storm is named when it reaches tropical storm strength with winds of 39 mph, and becomes a hurricane or typhoon when its wind speed reaches 75 mph. ;The National Weather Service of the United States has used girls' names to identify hurricanes in the Atlantic, Caribbean, and Gulf of Mexico since 1953 and the names were given in alphabetical order. ;Each name on the list starts with a different letter, for example, the name of the very first hurricane of the season starts with the letter A, the next starts with the letter B, and so on. The letters "Q", "U", "X", "Y" and "Z", however, are not used. ;A semi-permanent list of 10 sets of names in alphabetical order was established in 1971. This practice of giving girls' names to hurricanes changed recently. In 1980 a hurricane was given a man's name and was called Hurricane David. ;They also began using French and Spanish male and female names at this time. Hurricane season usually starts on June 1 and ends on Nov. 30. ;Often when an unusually destructive hurricane hits, that hurricane's name is retired and never used