在大学英语四六级考试中，单独考察的题几乎没有，但是语法知识点却贯穿整张试卷，下面是小编为大家整理的知识，希望可以为大家带来帮助，一起来学习一下吧。
特殊的虚拟语气词：should
1) It is demanded / necessary / a pity that…结构中的主语从句的谓语动词要用should 加动词原形， should 可省略。
句型：
(1)suggested It is
(2)importantthat… (should) do
(3) a pity
(1)suggested, ordered, proposed, required, demanded, requested, insisted; (should) do
(2)important, necessary, natural, strange a pity, a shame, no wonder
(3)It is suggested that we (should) hold a meeting next week. It is necessary that he (should) come to our meeting tomorrow.
2)在宾语从句中的应用 在表示命令、建议、要求等一类动词后面的从句中。 order, suggest, propose, require, demand, request, insist, command, insist (should) do I suggest that we (should) hold a meeting next week. He insisted that he (should ) be sent there.

注意： 如suggest, insist不表示"建议" 或"坚持要某人做某事时"，即它们用于其本意"暗示、表明"、"坚持认为"时，宾语从句用陈述语气。 The guard at gate insisted that everybody obey the rules. 判断改错: (错)You pale face suggests that you (should) be ill. (对) Your pale face suggests that you are ill. (错) I insisted that you ( should) be wrong. (对) I insisted that you were wrong.
3)在表语从句，同位语从句中的应用 在suggestion, proposal, idea, plan, order, advice等名词后面的表语从句、同位语从句中要用虚拟语气，即(should) 动词原形。 My idea is that we (should) get more people to attend the conference. I make a proposal that we (should) hold a meeting next week.