1,
与现在的事实相反:从句用过去式,主句用would/could/might/should/+动词原形。2、与过去的事实相反:主句用would/could/should/might/+have+
done , 从句中过去完成时。3、与将来的事实相反:主句用:should/could/would/might/+动词原形,从句用should do
(可能性最大),过去式(可能性一般)were to do (可能性最小)。 虚拟语气在各类从句中的用法 1,I lifted the chair so that I could be seen 我举起椅子就是为了能被看见 (状语从句)