1. wish 后的宾语从句
　a. 所希望的事与wish同时发生，从句用过去时，如：
　　I wish you didn't smoke too much.
　b. 所希望的事在wish之前发生，从句用过去完成时，如：
　　I wish I had paid more attention to my spelling.
　c. 所希望的事在wish之后发生，表示忠告或请求等，从句一般用would＋动词原形，如：
　　He wishes we would help him in the work.

2. 在表示愿望、请求、建议、打算、命令等意义的词，如 suggest, command, demand,
　decide, propose, order, recommend, request, require, desire, insist, urge等后的宾语
　从句中，以及这些词用于被动语态的主语从句中，都用 (should +) 动词原形，如：
　He suggested that the meeting (should) be held at once.
　It is desired that Tom (should) get everything ready by ten o'clock.

3. 上述动词转化或派生的名词以及idea, notion, no wonder, a shame, a pity等后的表语
　从句，主语从句或同位语从句中也用(should +)动词原形，如：
　Our decision is that the school remain closed.
　It's a pity that he (should) call black white.
　He made a request that the new electronic instrument (should) be tested at once.

4． 在It is necessary (important, desirable, essential, amazing, strange, urgent, vital,
　natural, unusual, possible), etc. 后的主语从句中也用(should +)动词原形，如：
　It is necessary that the problem (should) be solved at once.