<例句>
He should not drink and drive.
他不应该酒后开车。
<语法分析>
should在这个句子中是情态动词的用法，表示“应该”意思接近于ought to。作助动词时，should可用于第一人称，构成过去将来时态。在某些句子中，用should可以使口气显得更婉转，在某些宾语从句和主语从句里可以用来构成谓语，也用在虚拟条件句和条件从句中。在某些由in case, so that, lest等引导的状语从句中，也可以用should。
<触类旁通>
(1) I said I should be glad to help.
我说过我将乐于帮忙。
语法分析：should可用于第一人称，构成过去将来时态，在口语里大多用would。
(2) You should have been helping him.
你应该在帮助他。
语法分析：作情态动词用，后面可以用完成形式。
(3) I should be glad to talk to you.
我很高兴和你谈谈。
语法分析：用在某些句子里使语气更婉转，只用于第一人称。
(4) He determined that she should study music.
他决定她学习音乐。
语法分析：在某些宾语从句中构成谓语。
(5) It was necessary that he should work hard.
他用功很有必要。
语法分析：在某些主语从句里构成谓语。
(6) Should I be free thiss afternoon, I will come.
如果今天下午有时间，我就来。
语法分析：用在条件从句中，主句谓语可以用虚拟语气或陈述语气等。
(7) I should say she's over fifty.
我看她有五十多岁了。
语法分析：表示猜测。
<巩固练习>
(1) He considered how he ______answer.
(2) I _____ be grateful for your help.
(3) She arranged that I _____ go abroad.
(4) It is only right that he _____ have a share.
(5) How _____ I know?
(6) If I was asked to work on Sunday I _____ resign.
(7) She was terrified lest she _____ slip on the icy rocks.
<参考答案>
(1) should (2) should (3) should (4) should (5) should (6) should (7) should
