(1)、一些表示建议、要求、命令等的动词本身隐含说话者主观的意见。因此这些动词(或其变形，如名词，形容词，分词等)后面的从句应使用虚拟语气，即“should do”结构，其中的“should”常被省略。如：

　　表“提议、建议”的动词：suggest ,advise, propose, recommend, move(提议);

　　表“要求、主张”的动词：insist, require, request, demand , desire ;

　　表“命令”的动词：order, command.

　　例(1)I don’t think it advisable that Tom _____ to the job since he has no experience.

　　A. be assigned B. is assigned C. will be assigned D. has been assigned

　　(【答案】A)(2006年11月29题)

　　例(2)His mother insisted that he _____ the coat when going out.

　　A. put onB. puts onC. to putD. putting on

　　(【答案】A)(1999年58题)　　此处省略了should.

　　例(3)The doctor advised that Mr. Malan _____ an operation right away so as to save his life.

　　A. had B. would have C. have 　D. was going to have

　　(【答案】C)(1998年28题)　　此处省略了should.

　　(2)、It is necessary/important/essential/ vital/urgent / surprising/ amazing that引导的主语从句中，从句的谓语动词要用should+原形动词，should也可以省略。此类形容词的特点是表示重要性或吃惊。

　　例(1)it is vital that enough money_____collected to get the project started.

　　A. is B. be C must be D can be

　　(【答案】B)(2004年11月24题)

　　例(2)It’s urgent that a meeting _____ before the final decision is made.

　　A. will be arrangedB. must be arranged

　　C. be arranged　D. would be arranged

　　(【答案】C)(2003年4月45题)

　　(3)、以in case, lest, for fear that引起的状语从句，表示“以防，以免”。其形式为should+动词原形。如：

　　He took his raincoat with him in case it should rain.

　　他把雨衣带在身上以防下雨。