if条件句中doc虚拟语气.doc

if条件句中if 引导的条件句中，如果所说的与事实相反，则要用虚拟语气。其具体的规则如下：??? 主句?? 从句 与现在事实相反?? would/should/could+动词原形?? 一般过去时 与过去事实相反?? would/should/could have done?? 过去完成时 与将来事实相反?? would/should/could+动词原形 Should+动词原形/一般过去时/were to+动词原形 注意：虚拟语气中的be动词，一般用were，少用was(1)与现在事实相反，从句谓语动词用did(be用were，少用was )，主句谓语动词用would(should, could,might)+doIf the weather were fine , they would go for a swim. ( In fact it is rainy ,so they won’t go for a swim, )如果天气好， 他们就去游泳了。If we had time now , we should read it again . (In fact now we have no time to read it again . ) 要是现在有空， 我们就把它再看一遍。If John had his way [为所欲为], he would spend all of his time playing tennis. = John wants to play tennis often如果让约翰由着性子来，他会把所有的时间都用来打网球的If you dropped the glass , it would break . ( In fact the glass wouldn’t drop . ) (2)与过去事实相反，从句谓语动词用had done，主句谓语动词用 would(should,could,might)+ have doneIf he hadnt lived among the workers for so many years, he wouldnt have been able to write such a good novel假如他没有和工人一起生活这么多年，他不可能写出这么好的小说Mary could have gotten better grades if she had studied more= Mary did not get better grades because she did not study如果玛丽再刻苦一点，她会取得更好的成绩The project would have been approved [批准；赞成]if it hadnt been for the budget=The project was not approved because the budget was high[高的 [预算].如果不是预算的原因，这个项目是会被批准If we had needed to get in touch with them, we could have sent a telegram= We did not send a telegram because we did not need to get in touch with them. 如果我们当时需要和他们联系，我们会发电报的If we had arrived on time, we would have gotten good seats= We did not get good seats because we were late如果他主动向她提出邀请，她是会和他一起去的We would have been here sooner if we hadnt gotten lost= We were not here sooner because we got lost如果我们没有迷路的话，我们会早一点到达有I should have died of hunger if the Communist Party had not come in 1949=I am alive because the Communist Party came in 1949. 要是一九四九年共产党不来的话，我是会饿死的(3)与将来事实相反，从句谓语动词用did(should+do或were + to do)，主句谓语动词用 would(should,could,might)+do。If she should come , I would / should ask her for help . If