-2-

考点二

考点三

考点四

考点一

1.表示与现在事实相反:条件状语从句中谓语动词用过去式(be的过去式用were);主句中谓语用would/should/could/might+动词原形。 (2016·10浙江)If it were not stopped that long train,full of passengers would fall into the stream. 如果那列长长的满载乘客的火车不被拦住,全部乘客就会掉入溪流中。

2.表示与过去事实相反:条件状语从句中谓语用had+过去分词;主句中谓语用would/should/could/might+have+过去分词。 (2017·北京)If the new safety system had been put to use,the accident would never have happened. 如果新的安全系统投入使用,这次事故就不会发生了。