had better, should, ought to學(xué)習(xí)四要素.doc

had better, should, ought to學(xué)習(xí)四要素 had better, should, ought to 均為提建議型情態(tài)動詞，常用來勸告別人去做某事，沒有人稱和數(shù)的變化，學(xué)習(xí)時應(yīng)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(chuàng)新用法 should 可表竟然，強調(diào)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(xiàn)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(gòu)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(gòu)成一般疑問句時應(yīng)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(gòu)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(yīng)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(yīng)該做某事但實際未做，表達(dá)一種遺憾的感情色彩。 shouldnt / oughtnt to have done sth. 本來不應(yīng)該做某事但實際已做了，也表達(dá)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(jīng)開始了，你本來應(yīng)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(xiàn)在很難過，你本不該把這消息告訴她。 鞏固練習(xí) I. 從 A 、 B 、 C 、 D 中選出可以填入空白處的最佳答案。 1. This dictionary belongs to Rita. You _ it home without letting her know. A. had better not to take B. shouldnt have taken C. oughtnt take D. shouldnt be taking 2. Our money is very limited, so you _ so much money on so dear a skirt. A. shouldnt have spent B. shouldnt be spending C. neednt have spent D. oughtnt spend 3. You _ to your father like this, after all he is your father. A. neednt have spoken B. mustnt have spoken C. oughtnt to have spoken D. ought to not have spoken 4. I really cant understand such a beautiful girl like her _ be so rude. A. must B. would C. should D. might 5. Look, the books on the desk are all wet. You _ all the windows to keep the rain out. A. must have shut B. should have shut C. ought have shut D. can have shut 6. The little girl had better not stay up too late, _ she? A. does B. will C. had D. has 7. This is a very important project, so you _ plan it very carefully. A. ought to B. will C. dare D. need 8. You had better _ football near the street, its very dangerous. A. not to play B. dont play C. not play D. to not play II. 在下列各句的空白處填上適當(dāng)?shù)那閼B(tài)動詞，每空一詞。 1. Excuse me, may I sit here? Im afraid you _ _ not, because someone has taken it. 2. Tom, you _ have left home without telling your parents yesterday afternoon. 3. You _ _ have bought that book. It is so good. 4. I think you should be careful in all your work, _ you? 5. Your sister ought to put he