高中英語語法-had better, should, ought to學習四要素（一）
had better, should, ought to學習四要素（一）
had better，should，ought to 均為提建議型情態動詞，常用來勸告別人去做某事，沒有人稱和數的變化，學習時應注意下列幾點：
一、掌握基本用法
had better，should，ought to 含義及語氣有所不同，請看下表：
二 、掌握創新用法
should 可表竟然，強調驚訝的情緒。
I cant imagine this problem should be so easy.
我想像不出這個問題竟然這么容易。
had better 也可改為 had best ，其意義和用法不變。
Im busy now，so you had best go there alone.
我現在很忙，所以你最好單獨去那兒。
三、掌握句型變換方法
had better，should，ought to 均屬于助動詞，其疑問句、否定句及反意疑問句的構成均在自身形式上做變化。
1. 變成否定句方法
had better do 否定式為 had better not do，should do 否定式為 should not do 或 shouldnt do，ought to do 否定式為 ought not to do 或 oughtnt to do .
2. 變成一般疑問句方法
had better，should，ought to 構成一般疑問句時應分別將 had，should，ought 提到句首，其肯定與否定回答為 had / hadnt，should / shouldnt，ought / oughtnt .
3. 變成反意疑問句方法
had better，should，ought to 構成反意疑問句時通常使用 had / hadnt，should / shouldnt，ought / oughtnt 形式。
She had better water the flowers as soon as possible，hadnt she？
她最好盡快給花澆水，不是嗎？
All of us should take an active part in this activity，shouldnt we？
我們都應該積極參加這次活動，不是嗎？
They oughtnt to go fishing in this river，ought / should they？
他們不該在這條河里釣魚，是嗎？
四、掌握完成式用法
should 與 ought to 完成式意義和用法相同，可以通用。should / ought to have done sth. 本來應該做某事但實際未做，表達一種遺憾的感情色彩。shouldnt / oughtnt to have done sth. 本來不應該做某事但實際已做了，也表達一種遺憾的感情色彩。 had better 沒有完成式。
The meeting has already begun. You should have come here half an hour ago.
會議已經開始了，你本來應該半小時之前就到這兒。
She is very sad now. You oughtnt to have told her the news.
她現在很難過，你本不該把這消息告訴她。[1][2]
had better, should, ought to學習四要素（一）
had better，should，ought to 均為提建議型情態動詞，常用來勸告別人去做某事，沒有人稱和數的變化，學習時應注意下列幾點：
一、掌握基本用法
had better，should，ought to 含義及語氣有所不同，請看下表：
二 、掌握創新用法
should 可表竟然，強調驚訝的情緒。
I cant imagine this problem should be so easy.
我想像不出這個問題竟然這么容易。
had better 也可改為 had best ，其意義和用法不變。
Im busy now，so you had best go there alone.
我現在很忙，所以你最好單獨去那兒。
三、掌握句型變換方法
had better，should，ought to 均屬于助動詞，其疑問句、否定句及反意疑問句的構成均在自身形式上做變化。
1. 變成否定句方法
had better do 否定式為 had better not do，should do 否定式為 should not do 或 shouldnt do，ought to do 否定式為 ought not to do 或 oughtnt to do .
2. 變成一般疑問句方法
had better，should，ought to 構成一般疑問句時應分別將 had，should，ought 提到句首，其肯定與否定回答為 had / hadnt，should / shouldnt，ought / oughtnt .
3. 變成反意疑問句方法
had better，should，ought to 構成反意疑問句時通常使用 had / hadnt，should / shouldnt，ought / oughtnt 形式。
She had better water the flowers as soon as possible，hadnt she？
她最好盡快給花澆水，不是嗎？
All of us should take an active part in this activity，shouldnt we？
我們都應該積極參加這次活動，不是嗎？
They oughtnt to go fishing in this river，ought / should they？
他們不該在這條河里釣魚，是嗎？
四、掌握完成式用法
should 與 ought to 完成式意義和用法相同，可以通用。should / ought to have done sth. 本來應該做某事但實際未做，表達一種遺憾的感情色彩。shouldnt / oughtnt to have done sth. 本來不應該做某事但實際已做了，也表達一種遺憾的感情色彩。 had better 沒有完成式。
The meeting has already begun. You should have come here half an hour ago.
會議已經開始了，你本來應該半小時之前就到這兒。
She is very sad now. You oughtnt to have told her the news.
她現在很難過，你本不該把這消息告訴她。[1][2]
