1. 虚拟语气在if条件状语从句中的用法

1.动词过去式(或were) 2.助动词（过去式）+动词原形

should/ would /could/ might+动词原形

had+过去分词

should/ would/could /might + have+过去分词

should/ would/ could/ might +动词原形

1.should+动词原形 2.动词过去式 3.were to+动词原形