现在完成时难点瞬间动词转换成延续性动词

现在完成时之瞬间动词转变成延续性动词1、 forsince:1) for+一段时间，常常可以发现for+数字，for three months for a long time for many years 2) Since+时间点，常常可以发现a. since+月份，年份，表示时间的几点 since September since 1990 since 7 oclockb. since+一段时间+ago； since two years ago since ten months agoc.since+ last+. since last month since last year2、 现在完成时的结构式 hashave done 请注意第三人称：shehe人名.+has 3、 当句子为肯定句，且居中出现forsince的时候，句中的时态要用现在完成时，且句中的动词要用延续性动词。当句子为否定句时，句中的动词可以为瞬间动词，表示某个动作不发生的状态已经持续了.4、 在有forsince的现在完成时的从句中，如何将瞬间动词转换成延续性动词以borrowkeep为例子They borrowed it last week. They have kept it since last week.分析：1） 我们已经知道现在完成时的标志就是hashave done，因此第一步就是看主语，主语时They，我们选择have done。2） 因为borrowkeep.而keep过去分词：kept，因此，have borrowed就需要改成have kept.3） Since后面只能接时间点，而last week就是一个时间点，因此，since后面直接填写last week。5、 常考的瞬间动词： 原形 过去式 过去分词 动词原形 动词过去分词1. die-be dead die died died be dead been dead2. borrow-keep borrow borrowed borrowed keep kept3. leave-be away from 4. buy-have buy bought bought have had5. begin-be(on) begin began begun be been6. join-be a member of be in join joined joined be in been in7. become-be become became become be been8. Openclose-be open open opened opened be open been open9. finish-be over finish finished finished be over been over10. put on-wear put put put wear worn11. catch a cold-have a cold catch caught caught have had12. go to-be in go went gone be in been in13. get to know-know get got got know known14. Arrive inat-be in arrive arrived arrived be in been in15. Movecomeget to-be in 16. go out-be out go went gone be beenMovecomeget to-be in be in been in举例Mr. Smith came to this school in September.Mr. Smith _has_ _been_ at this achool_since_ September.分析：1, come-came-come2, 本来应该是填写has come to，