在表示建议、命令、要求、忠告等动词的后面，其宾语从句的谓语用“should+动词原形”表示虚拟语气

常用的此类动词有：

表示“要求”的：ask, desire, request, demand, require, beg

表示“提议、劝告、建议”的：move, prpose, suggest, recommend, advise, vote

表示“决定、命令”的：decide, order

表示“主张”的：maintain, urge

表示“同意、坚持”的：consent, insist

例：The doctor suggested that he (should) try to lose his weight.

He insisted that we (should ) tell him the news.

上述动词的名词形式，demand, desire, requirment, advice, order, decision, recommendation, suggestion, 以及necessity, preference, plan, motion, idea等名词，其后的表语从句或同位语从句，也用“should+动词原形“表示虚拟语气。现代英语，特别是美国英语，常省去“should”，例：

The advice is that we (should) leave at once.

He idea that we (should)visit Great Wall was warmly welcomed.