语法考点之一 ：虚拟语气考点1. If从句中的虚拟语气1、与过去事实相反：从句sb had done，主句sb would(should, could, might)+ have done；2、省略if，从句的语序用到装，即将were, had或 should移至主语的前面，但否定词not不前移。3、与将来事实相反：从句sb did (should+do或were+to do)，主句sb would (should, could, might)+do。4、错综条件句：主句与从句的动作发生在不同的时间段。比如：从句对过去虚拟，而主句对现在虚拟，即从句sb had done，主句sb would(should, could, might)+do；考点2：表示建议、要求、命令等动词如insist, order, command, suggest, advise, propose, ask, require, request, demand引导的从句及it引导的相应的分词、名词和形容词从句，谓语用（should)+动词原形。 考点3：It
