Unit 5 Using Laguage2 Language points 课件-2021-2022学年高中英语人教版（2019）选择性必修第一册.pptxVIP

Unit 5 Using Language 2 Language pointsCHEMICAL VERSUS ORGANIC FARMINGChemical pesticides and artificial fertilisers have been in widespread use in farming since the middle of the 20th century. When they were first introduced, many farmers welcomed them as a great way to fight crop disease and increase production. Over time, however, what some scientists have found is that their long-term use can sometimes harm both the land and people’s health.此句中包含两个从句，分别是what引导的____主语从句，what在此从句中充当___语； 以及that引导的_____从句，that在此从句中___成分；____实际意义，但___省略Chemical pesticides and artificial fertilisers_________(be) in widespread use in farming since the middle of the 20th century. When they were first introduced, many farmers welcomed them_______ a great way to fight crop disease and increase production. Over time, _________, what some scientists have found is ________ their long-term use can sometimes harm both the land _______ people’s health.have beenashoweverthatandFor example, pesticides can damage the land by killing not only harmful bacteria and insects, but also helpful ones. In addition, these chemicals can stay in the soil and underground water sources for a long time. This affects the crops grown on the land and, in turn, the animals and humans who digest them. Many people worry that these chemicals may make them ill and even cause cancer. In fact, some pesticides like DDT have been prohibited in most countries because of the damage they cause to people and the environment. As for chemical fertilisers, crops grown with them usually grow too fast to be rich in nutrition. They may look beautiful on the outside, but inside there is usually more water than essential minerals, and they often have less flavour as well.此句中grown on the land 是过去分词短语做_____语；修饰_____; 此句中的who digest them是_____从句，其先行词是_____essential: essence本质；实质；in essence从本质上讲be essential to 对....很重要It is essential (for sb) to do sth(对某人来说)做某事很重要It is essential that...(should) do 做...很必要1.Water and food are essenti