新人教版选修六Unit3Ahealthylife-Grammar-It的用法[课件].ppt

Grammar ;due to 6. stress addicted 7.quit eventually 8. drugs manage 9. alcohol cigarettes 10. adolescents; Smoking __________, drinking _______ or taking other_______ produce many harmful effects and have no real benefits. So why do ___________do it? Some begin because they believe it makes them look cool. Others think it will help with _______. In their life possibly ________ pressure from their parents or teachers.; Some just want to see what it is like. What they don’t realize is that they will get into the habit and ________ become ____________. It will then be difficult to ______the habit. A few people ________to quit easily but for many it is a very painful process. Of course, the best way to deal with these drugs is not to start in the first place.;Grammar;Discovering “It”;1. it的最基本用法是作代词，主要指刚提到的事物，以避免重复: Xi’an is?a?beautiful?city, isn’t?it? 2. 也可以指动物或婴儿(未知性别的婴儿或孩子): Is this your dog？No, it isn’t.;it有时并不指具体的东西，而泛指天气、时间、日期、距离、价值、度量、温度、环境等，称为非人称的it： 指天气： It is a lovely day, isn’t?it? It is a bit windy.2. 指时间: It was nearly midnight when she came back. 3. 指环境: It was very quiet in?the?café. 4. 指距离： It is half an hour’s?walk?to the city centre from my home.;5. 指日期： --Whats the date today? --Its May 1, 2007. 6. 指季节： It is summer now. 7. 指度量： It is about 5 kilograms. 8. 指价值： ----Whats the cost of the T-shirt? ----It is 150 yuan. ;替代作主语的从句、动词不定式、动名词，而把真正作主语的从句、动词不定式、动名词置于句尾。;（1）It be adj.（for sb.）to do sth. 此处adj. 通常为描述事件的形容词：easy，difficult，hard，necessary，unnecessary，possible，impossible，likely，unlikely，right，wrong，important，unimportant，legal，illegal，well-mannered，ill-mannered，polite，impolite，clear，obvious，certain，suitable，proper，fit，useful，useless，dangerous… It is illegal（for a teenager）to drive a car without a license. 　　;（2）It be adj. of sb. to do sth. 此处adj. 通常为描述人的形容词：kind，unkind，nice，rude，cruel，considerate，thoughtful，thoughtless，careful，careless，silly，f