2.在“it is+过去分词+that”从句中

“It is/was+过去分词+that”从句中用常用虚拟语气，表示愿望、建议、请求等主观意向，谓语用“should+动词原形”或只用动词原形。这些过去分词常见的有requested，suggested，desired，recommended，decided，demanded，insisted，ordered，proposed，ordered，urged，advised，arranged，required等。

It is requested that Professor Li(should)give us a speech．

要求李教授给我们发表演讲。

It has been decided that the meeting(should)be postponed till nextSaturday．

已经决定会议延期在下星期六召开。