虚拟语气也是一个难点。所谓虚拟语气是表示说话人的愿望、假设、猜测或建议，而不表示客观存在的事实。它通过句子的谓语动词的特殊形式来表示。现归纳如下：纯假设，用虚拟，动词时态退一级：条件句，分主从，主句谓语前加would (should,could，might);表愿望,用虚拟，wish后面接宾语(从句)：现在过去与将来，动词时态退一级：提建议，用虚拟，宾语(从句)动词用(should)do：俩建议，三要求，再加坚持与命令(suggest,advise,demand,require,request,insist,order)：It is time和eoukd rather,后接丛句用虚拟：部分主语从句中， 谓语用虚拟结构 (It is necessry /important/natural/natural/strange/strange that……should do)。 下面举例说明：

A、If you came tomorrow,we would have the metting. (条件句虚拟)

B、Without air,there would be no living things.(同上)

C、We wish we had arrived there two hours earlier.(表示愿望虚拟)

D、He demanded that we (should)start right away.(表示建议虚拟)

E、It is(high)time that we left (should leave)now.(特殊从句虚拟)

F、I would rather you gave me the book.(同上)

G、It is necessary that we should clean the room everyday，(主语从句虚拟)

H、He speaks English so fluently as if he were English. (特殊从句虚拟)

总之，语法是从语言实践中总结出来的规则，要边学边寻找规律，以提高学习效率。在学习中不能只记一些语法规则，要进行实践练习。通过练习，可以发现和纠正错误，而且有利于况固所学知识。

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