3、re)should/would/could/might+动词原形与过去事实相违背had+过去分词should/would/could/might+have+过去分词与未来事实相违背1)should+动词原形2)were+动词不定式3)过去式(动词是Be也可以用were)should/would/could/might+动词原形 1.与现在事实相反的虚拟条件句,条件从句的谓语用动词的过去式(be的过去式用were),主句的谓语用should(would,might,could)+动词原形。 如: If