unit 1 tales of unexplained课件14(牛津高中必修2）.ppt

* 1.Present Perfect Tense 2.Present Perfect Continuous Tense Ⅰ、现在完成时 1.现在完成时的构成 2.现在完成时的用法 Ⅱ、现在完成进行时 1.现在完成进行时的构成 2.现在完成进行时的用法 Ⅲ、现在完成时和现在完成进行时的比较 1.现在完成时的构成： 主动式:have/has done 被动式:have/has been done 1.现在完成时 We ___________________(already open) the window. 过去的动作: we opened the window. 对现在的影响: The window is open. have already opened 2.现在完成时的用法 The boys are tired. They ________________ (just play) a ball game. 过去的动作 : The boys played a ball game. 对现在的影响: The boys are tired. have just played 现在完成时表示过去发生或已完成的动作，或某一动作对现在造成的影响或结果。通常与表示包括现在在内的时间副词just, already, before, yet, never, ever, lately, recently等状语连用。 小结： 现在完成时用法1---已完成、影响性用法 already:用于肯定句; yet:用于否定和疑问句 Daniel __________ (live) in Beijing since he came to China. has lived past future now came live has lived 现在完成时表示过去已经开始，持续到现在,也许还会持续下去的动作或状态。可以和表示从过去某一时刻延续到现在（包括现在在内）的一段时间的状语连用。如： ① for和since， ② so far, up to now, today, until/till…, this week (month, year) ③ during /over /in the past few years (weeks, months…) 现在完成时用法2---未完成用法 小结： Fill in the blanks: ①. a. She has learnt English 3 years. b. She has learnt English 3 years ago. c. They have lived here _____1990. for since since ② I (see) her so far. ③ What _________________ (happen) to the USA in the past 35 years? haven’t seen has happened Since 的补充用法 A.主句+since+从句 Great changes have taken place since you left. B. It is +时间段+ since+从句 It is / has been two years since I left my hometown. b. It was /had been two years since I had left my hometown. c. It is years since I smoked . d. It is years since I began to smoke . I went to Egypt in 1986. I went to Egypt in 2004. I __________ (be) to Egypt twice. have been 现在完成时可过去发生过一次或多次的情况，也可以说是一种经历。 现在完成时用法3---经验性用法 I （not see） anything so beautiful in my life. haven’t seen 小结： √ ( ) 1. He has come here. ( ) 2. He has come here for 3 days.