<例句>
What ought I to say to him?
我该对他说些什么呢?
<语法分析>
ought总是和to一起用，可以表示义务、约束力，意为“应该，应当”，语气比should强，比must弱。还可以表示事与愿违，意为“本应该，本当”。在口语中表示愿望，意为“......才好”。ought后面的不定式可用完成形式、进行形式或被动形式等。ought to 一般不用过去时，在宾语从句中，可用于过去时。ought还可以表示揣测的意味。
<触类旁通>
(1) I ought to write to her today.
我今天应当给她写信。
语法分析：表示“应该，应当”
(2) She ought to have stopped at the traffice lights.
在红绿灯前她本应该停车。
语法分析：后面的不定式可用完成形式。
(3) I ought to be leaving now.
我现在该走了。
语法分析：后面的不定式可用进行形式。
(4) Something ought to be done about it.
对此应当想些办法。
语法分析：后面的不定式可用被动形式。
(5) He ought to pass his test.
他应当能通过考试。
语法分析：ought还可以表示揣测。
(6) The chils ought not to hace been allowed to go alone.
本不该叫孩子一个人去。
语法分析：表示事与愿违，意为“本应该，本当”。
(7) He said she ought to leave for Japan.
他说她该动身去日本。
语法分析：在宾语从句中，ought to 可用于过去时。
<巩固练习>
(1) You ought to ______[read] this novel.
(2) Ought I to ______[write] to say thank you.
(3) She ought to ______[come] to the meeting, but I didn't see her.
(4) You ought not to _____[drive] so fast.
(5) She ought to _____[isolate].
(6) The water ought to _____[boil] by now.
(7) I ought to _____[hear] from her soon.
(8) There ought not to _____ must noise in a hospital.
(9) She ought to ______[do] it yesterday.
<参考答案>
(1) read (2) write (3) have come (4) have been driving (5) be isolated (6) have boiled (7) be hearing (8) be (9) have done
