★今天介绍的这个英文句型中，常含有一个表示“有必要的”之类的形容词。在这种结构中，that从句中须使用助动词should，但should常予以省略，而直接接动词原形。常见的此类形容词有“important/imperative/necessa-ry/essential有必要的、urgent迫切需要的、desirable合意的，值得的、advisable明智的，适当的”。其句型如下：

It is important/imperative/necessary/…+that+主语+(should)+动词原形

★实战演练：

It is important that you (should) think before you say or do anything.

在你说或做任何事情之前先想一下是很重要的。

It is imperative that Carlos (should) get married before his girlfriend changes her mind.

卡洛斯应该赶紧在他的女友改变心意之前娶她。

It is necessary that you (should) be punctual.

做到守时是必须的。

It is essential that the teachers (should) learn to be patient.

做老师的有必要学会有耐心。

It is urgent that food and clothing (should) be sent to the sufferers.

急需将食物和衣服送给灾民。

It is desirable that the airplane (should) be as light as possible.

飞机尽可能轻一些是更为合理的。

It is advisable that you (should) take precautions before the typhoon arrives.

在台风来之前先采取预防措施是明智的。