仁爱版九年级英语上册精品课件U4T2SD.ppt

* 哈尔滨市阿城区杨树民主学校 魏培培 福建省晋江市罗山中学 王淑春 Unit 4 Amazing Science Topic 2 When was it invented? Have you ever got lost somewhere? What method did you use to find your direction? （影片） Read and discuss the following questions. 1. What would you do if you lose your way in a forest? 2. How did the early explorers know where they were? 3. What is GPS? Is it useful to us? 4. What do you think GPS will be used for in the future? What is GPS? GPS即全球定位系统(Global?Positioning?System)，简单地说，这是一个由覆盖全球的24颗卫星组成的卫星系统。这个系统可以保证在任意时刻，地球上任意一点都可以同时观测到4颗卫星，该观测点可以通过接收到的信号 计算出经纬度和高度，以便实现导航、 定位、授时等功能。这项技术可以用 来引导飞机、船舶、车辆以及个人， 安全、准确地沿着选定的路线，准时 到达目的地。  疑难讲解 1.in …direction 按/朝……方向 e.g. A motor bike hit a truck in the opposite direction. 2. work well 奏效；起作用 e.g. The medicine worked well. 3. as long as 只要；长达 e.g. You can go out to play as long as you finish your homework. e.g.I have taught English as long as nine years. Read and answer the question. A thief stole a beautiful cellphone from a young girl. He ran away very quickly and then hid in a secret place. To his surprise, when he was using the cellphone, he was caught by the police. Do you know why Bluetooth Bluetooth is a short distance wireless communication technology. It provides coverage (覆盖） of up to 100 meters. It’s a low power technology that can be used to connect cellphones or computer with other devices. A bluetooth headset 长长见识 根据首字母提示，完成短文。 Thanks to GPS, we can exactly know w _____we are now. GPS is like a man-made “star”. It can be u____ in any place and any weather condition to find out our p________. In the past, the early explorers had to use stars in the s____ to tell them where they were, however, this method didn’t work well when the weather was bad. So GPS is a great invention that can help humans to better e________ our planets. here osition sed ky xplore What have you learnt about in t