主句中的动词、名词、形容词如表示要求、建议、命令或愿望等含义，与其相关的名词性从句(主语从句、宾语从句、表语从句和同位语从句)中的谓语动词要用虚拟语气。

　　1.主语从句中的虚拟语气

　　It is desired/suggested/proposed/necessary/important/

　　strange/natural/a pity/a shame＋that从句，从句中的谓语动词用"(should)＋动词原形"。

　　(1)表示建议或命令

　　It is important that we (should) work out a study plan.重要的是我们要制订出一个学习计划。

　　It is requested that Miss Zhang (should) give a performance at the party.

　　张小姐被请求在晚会上表演一个节目。

　　It is suggested that each student (should) sing a song in English.

　　有人建议每个学生都要唱一首英文歌曲。

　　It is demanded that he (should) leave at once.

　　他被要求立刻离开。

　　(2)表示惊讶

　　It is strange that he (should) have failed to see his own shortcomings.真奇怪，他竟看不到自己的缺点。

　　It is a pity/shame that I (should) be at school instead of lying here in hospital.

　　真可惜，我应该在学校而不是躺在医院里。

　　2.表语从句和同位语从句中的虚拟语气

　　在advice，suggestion，proposal，order，idea，request等名词后的表语从句和同位语从句中要用虚拟语气。谓语动词用"(should)＋动词原形"。

　　My idea is that they (should) pay 100 dollars.

　　我的想法是他们得付100美元。

　　I make a proposal that we (should) go out for a walk this afternoon.我建议我们下午去散步。

　　The suggestion that education (should) be reformed is reasonable.教育应该改革的建议是合理的。

　　3.宾语从句中的虚拟语气

　　当主句的谓语动词为表示命令、建议、要求等的动词，如insist，order，demand，suggest，advise，propose，recommend，demand，require，request，desire等时，其后的宾语从句中要用虚拟语气，谓语动词为"(should)＋动词原形"。

　　He ordered that all (should) take part in the work.

　　他命令所有人都要参加这项工作。

The workers demanded that their wages (should) be raised by 10 percent.工人们要求增加百分之十的工资。