Unit 5 Educational exchanges第 3 课时 语法栏目导航课 时 精 讲课 时 过 关课 后 拓 展课 时 精 讲一、现在完成时态的时态意义。 1．现在完成时态表示过去发生的动作对现在造成的影响或结果。如： I have already posted the letter.(The letter is not here.) 2．现在完成时态表示过去某时刻开始持续到现在的动作或情况。如： We’ve waited for 5 hours. 二、现在完成时态的构成：have/has+动词过去分词 过去分词变化规则： 1．一般直接在词尾加上-ed。如：look—looked；post—posted 2．以 e 结尾的动词，直接加-d。如：move—moved；use—used 3．辅音字母+y 结尾，变 y 为 i 再加-ed。如：carry—carried 4．重读闭音节单词需双写末尾辅音字母，再加-ed。 如：stop—stopped；plan—planned 【小试牛刀】请写出下列不规则动词过去式和过去分词。 do____ _____ be_________ ______ learn___________ _____________ teach_______ ________ spend_______ ______ have____ _____ keep______ _____ make______ ______ see_____ _____ come_____ _______ win______ ____ find______ _______ go______ _____ run____ ______ sell______ ______ diddonewas/werebeen learned/learntlearned/learnttaughttaught spent spenthadhadkept kept made made saw seencamecomewon won foundfoundwent goneranrunsold sold 三、现在完成时态的时间状语。 现在完成时的常见时间状语有：for, since, so far, by now, ever, never, just, yet, in the past … years 等。 We’ve learnt 3000 words so far. They haven’t finished their task yet. He has collected 500 stamps since ten years ago. The young men have travelled 10 countries in the past ten years. 四、几组易混淆词用法辨析。 1．already & yet already 常用于肯定句；yet 常用于否定句和疑问句。如： Tom has already finished his homework. Tom hasn’t finished his homework yet. Have you seen the Great Wall yet? 【小试牛刀】请用 already 和 yet 完成下列句子。 (1)Have they begun Unit 11 ____? (2)He has left the office ________. (3)I have ________ finished my ...
