精选优质文档-倾情为你奉上1. (表示条件)如果 ,主句用将来时，if从句用现在时表示将来He will come if you invite him. 如果你请他,他会来的。 2. (表示虚拟)假如,要是 1）时态：可以表示过去，现在和将来的情况。它的基本特点是时态退后。a. 同现在事实相反的假设。句型 ： 主句 should( would) +If they were here, they would help you.b. 表示于过去事实相反的假设。句型： 主句 should(would) have+ 过去分词If she had worked harder, she would have succeeded. The rice would not have been burnt if you had been more careful. If my lawyer had been here last Saturday, he would have prevented me from going. If he had come ,
