Unit3 The World of science Using language课件 2021-2022学年外研版高中英语必修第三册

Unit 3 the world of science Using language 现在完成时 现在完成时表示过去的动作或存在的状态对现在造成的影响或结果，过去的这个动作或状态也有可能持续下去。 用法： 表示一个动作刚刚结束或完成，但这个动作所造成的状态或影响依然存在，即表示过去的动作对现在的影响或结果，强调现在的情况，常与副词just, already（多用于肯定句或疑问句）, yet（常用于疑问句或否定句句尾）连用。 表示从过去到现在曾经发生过或经历过某事，表达一种经验或经历，常与副词ever，never，once，twice，before等连用。 常与for或since连用。For 后面接一段时间；since后接时间点或表示过去时间的时间状语从句。 特殊句型 【This/That/It is the first/ second/ third… time that…】 【This/That/It is the+形容词最高级+名词+从句】 【It is/ has been…since...(过去式)】 This is the first time that I ______________(watch) the play. This is the best film that I ______________(see). It ___________(be) six years since I came here. have watched have seen has been 现在完成时练习一 1、During the last three decades, the number of people participating in physical fitness programs _____________(increase) sharply. 2、After several years of observation, the research group____ ______ (arrive) at the conclusion that language acquisition is faster when students are exposed to the situation where it is spoken. 3、Simon_____________(attend) his father for such a long time that he understands almost every gesture of his father’s. 4、It is the first time that the local education authority ________ (make) such strict requirements on going-to-school time for primary and middle school students. 5、Over the last few years, the number of students participating in volunteer programs ______________ (increase) sharply in our school. has increased has arrived has attended has made has increased 6、Researchers believe that since 2010 an average of nearly 35,000 elephants _____________ (kill) annually on the continent. 7、With the help of high technology, more and more new substances _______________ (discover) in the past years. 8、In the past few centuries，the lighthouses along North Carolina’s coast __________________ (recognize) as signs of safety for travelers at sea. 9、I complained to the manager of the hotel about the poor service last week, but up to now，I ____________ (receive) his reply. have