八年级英语下册 外研版 Module 3 Journey to space(Unit 3).ppt

外研版·八年级英语下册 Module 3 Journey to space Unit 3 Language in use 语法：现在完成时 当我们要表达“某人曾经做过某事”, “某人已经做了某事”等意思时, 英语要用“现在完成时”来表达。 现在完成时的结构： has/have + done (动词过去分词) 肯定句 否定句 疑问句 I / We/ You / They have done… I /We/You /They have not (haven’t) done… Have you/they done…? He/She has done… He/She has not (hasn’t) done… Has he/she done…? 表达“刚刚做完某事”、“已经做完某事”时，使用现在完成时。如: I have just heard the news. 我刚听到消息。 Astronauts have already been to the moon. 宇航员已经去过月球了。 We have just started to explore other planets. 我们才刚刚开始探索其他行星。 just “刚刚”，already “已经”，两者都用于肯定句中，一般置于have/has之后。 否定句中则用yet, 表示“还（未）”。如： The scientists have not heard from it yet. 科学家还没有收到它发出的信息。 Man has not discovered any life in space yet. 人类尚未在太空中发现生命。 常与现在完成时连用的副词： 肯定句: 疑问句和否定句: already, never, ever, just 一般置于助动词have/has之后，过去分词之前; yet常置于句末。 already, just, ever, yet, never already, just, ever ever, yet, never 现在完成时表示该事件是在现在之前 的某一个时间里发生的， 重点在于强调这一动作与 现在的影响 一般过去时只表示过去的某一具体时 间发生的事情 I have just been to London. I went there last month. 我刚去过伦敦，是上个月去的。 I have already finished my homework. I finished it an hour ago. 我已经写完作业了，一个小时之前完成的。 A: Where have you put my book? I can’t find it. B: I put it on your desk yesterday. 当 A 问对方把自己的书放在何处时，他在意的是书目前在哪儿，故用现在完成时。 B的回答着重的是当时的动作，故用一般过去时。 无明确过去时间状语时，判断使用现在完成时还是一般过去时的标准是： 看该行为是否对现在有影响，即该句强调或在意什么，着重点就在那里。 A: Would you like to go and see the film with me tonight? B: Sorry, I ___________ it already. (see) Practise have seen 1. Complete the news with already, just and yet. Astronauts have (1)_______ been to the moon but they have not been to any other planets. However, a spaceship has (2) _____ arrived on Mars and it has (3) ______ sent back photos of the red planets. Is there life on Mars? We do not know (4)____. already just already yet have (has) been to 表示“曾经去过……” “到……去过了” have/has gone to 表示去了,还没有回来 。 3. Complete the sentences with the expressions in the box. have/has been have/has gone 1.