英語有個很有用的結構，就是：疑問詞+不定式動詞(question word + to-infinitive)。
疑問詞是疑問代詞“who, whom, what, which, whose”和疑問副詞“when, where, how, why ”。此外，連線詞“whether”也適用。
“疑問詞+不定式動詞”結構有何功用呢?其主要功用有下列五種：
⑴當主語，如：
● When to hold the meeting has not yet been decided.
● Where to live is a problem.
● How to cope with the rising cost of living becomes a daily discussion topic.
⑵當賓語，如：
● We must know what to say at a meeting.
● He could not tell whom to trust.
● Do you know how to play bridge?
⑶當補足語，如：
● The problem is where to find the financial aid.
● The question is who to elect.
⑷當名詞同位語，如：
● Tom had no idea which book to read first.
● Do you have a rough impression how to do it?
⑸當賓語補足語，如：
● Jim is not sure whose to choose.
● Mary and John are not certain whether to get married or not.
適用於“疑問詞+不定式動詞”的動詞包括：“know, see, decide, tell, ask, consider, discover, explain, forget, guess, hear, imagine, inquire, learn, remember, think, wonder, understand”等。
有點值得特別注意的是：當這結構當賓語時，它的作用等於名詞分句，例如：
● I could not decide which dictonary to buy. / I could not decide which dictionary I should buy.
● Jack did not know where to find such a good teacher./ Jack did not know where he could find such a good teacher.
有些動詞，如“ask, show, tell, advise, inform, teach”等，可以先有個賓語，然後才接著加上適當的“疑問詞+不定式動詞” 結構。例如：
● The chief technician showed the apprentice how to repair the machine.
● Have you told him where to get the application form?
綜上所述，可見“疑問詞+不定式動詞”結構是個形象清新，既容易用又不容易出錯的特別結構，可以多多運用。
九年級英語上冊知識點：垂懸結構所謂垂懸結構(The Dangling Construction)就是一個句子成分，如分詞短語，不定式動詞短語等，找不到被修飾的主語或被修飾的物件不合邏輯。垂懸結構是種錯誤的句法，應該避免。
下面是三種常見的垂懸結構及其改正方法：
⒈垂懸分詞或分詞短語，如：
① Climbing up the hill, several boars were seen.
這句子裡的現在分詞短語(present participial phrase)修飾主語“several boars”是錯的;改正方法有二：
(a)確定是邏輯主語，使句子變成“Climbing up the hill, the explorers saw several boars.”
(b)把現在分詞短語擴大為副詞分句(也稱狀語從句)：“When the explorers climbed up the hill, they saw several boars/ several boars were seen.”
⒉垂懸副詞短語，如：
② After putting a shrimp on the hook, the fish began to bite.
這句的副詞短語(adverb phrase)和主語“the fish”有什麼邏輯關係呢?真正的邏輯主語應該是“the fisherman”或“the angler”才對。改正方法和例①同：
(a) After putting a shrimp on the hook, the fisherman found that the fish began to bite.
(b) After the fisherman had put a shrimp on the hook, the fish began to bite.
⒊垂懸不定式動詞短語，如：
③ To write well, a lot of practice is needed.
④ To be a loyal employee, a sense of belonging is a must.
這兩個句子的不定式動詞短語(infinitive phrases)並不能修飾“practice”和“a sense of belonging”，真正的主語必須是“ 人”，如：
(a) To write well, one needs a lot of practice/a person has to practise a lot.
(b) To be a loyal employee, he or she must have a sense of belonging.
上述三類垂懸結構中，第一類發生的頻率最高，必須注意。但是在下列三種情況下，分詞短語是對的，它們並非垂懸結構：
第一，獨立結構(The Absolute Construction，見3月7日《中英合談》)中的分詞短語有自己的主語，所以不是垂懸結構。例如：
① Such being the case, we can go home now./……it is not wrong to call it a day.
第二，當分詞含有介詞或連詞性質時，它不需要邏輯主語，所以沒有垂懸問題存在。例如：
② Owing to a lack of funds, the project has to be discontinued.
③ Provided that there is sufficient time, everyone can do the job better.
第三，當分詞短語是用來表示說話者的態度或意見時，也不需要邏輯主語，因此也不存在著垂懸問題。例如：
④ Judging from his facial look, the news must have been terrible.
⑤ Taken as a whole, there is nothing wrong with the logic behind that idea.
九年級英語上冊知識點：形容詞字尾不可亂加下面這則廣告中的形容詞“irresistable”裡的字尾( suffix)不對，應該把“-able”改為“-ible”：
“We offer: competitive monthly salary, weekly incentives, attractive transport allowance, incentive trips and irresistable performance bonus.”
到底是“-able”，還是“-ible”?這兩者有何不同?
現在先從形容詞的其他字尾談起。
形容詞字尾分兩大類。一類是加到名詞上的;另一類是加到動詞上的。
㈠加到名詞上的主要有：① -y，如：bloody, dirty, healthy, juicy, muddy; ② -ly，如：costly, friendly, lovely, orderly, timely;③ -ful，如：careful, faithful, helpful, peaceful, useful;④ -less，如：careless, harmless, noiseless, senseless, useless;⑤ -ous/-ious，如：dangerous; courageous, envious, mysterious;⑥ -al/-tal/-ial/-tial，如：accidental, horizontal, colonial, influential;⑦ -ic/-etic/-atic，如：artistic, sympathetic, systematic;⑧ -ish，如：childish, foolish, selfish;⑨ -like，如： life-like, business-like, war-like;⑩ -ed/-en，如：skilled, horned, golden, wooden.
㈡加到動詞上的有：① -ent/-ant，如：dependent, different, observant, pleasant;② -able/-ible，如： agreeable, comfortable, defensible, sensible;③ -ive/-tive/-ative/-itive，如：active, attentive, imaginative, sensitive;④ -ed/-en，如：advanced, noted, stolen, swollen;⑤ -ing，如：annoying, disgusting, entertaining.
-able/ible 出現在第二類字尾中，“-able”字尾的形容詞屬英語體系的字：“-ible”字尾的形容詞則來自拉丁體系。前者數量大，後者數量少，主要的是下面這些，可以特別留意：
accessible, apprehensible, audible, compatible, contemptible, convertible, corrigible, destructible, digestible, divisible, defensible, edible, eligible, exhaustible, fallible, feasible, flexible, forcible, horrible, illegible, intelligible, negligible, perceptible, possible, responsible, resistible, sensible, suspectible, tangible, terrible, visible.
現在順便把名詞、動詞和副詞主要字尾提出，作為參考：
⑴名詞字尾
-ment, -t, -ture, -ion/-ition, -al, -ance, -ent, -er, -ant 等。這些名詞字尾都要加到適當的動詞上，如：arrangement, restraint, fixture, celebration, extension, competition, renewal, assistance, resident, exporter, attendant.
-ness, -y/-ty/-ity, -th, -ce/-cy 等，可以加到適當的形容詞上如：darkness, kindness, honesty, loyalty, simplicity, truth, warmth, importance, absence, ungency, efficiency.
⑵動詞字尾：
加到名詞上的有 -en, -ise/-ize, -fy, -ate，如：frighten, apologise, beautify, motivate.
加到形容詞上的有 -ise/-ize, -en，如：modernise, realise, brighten, weaken.
⑶副詞字尾：
-ly，可以加到形容詞和某些名詞上，如：beautifully, clearly, leisurely, weekly.
每個字尾都有一定的意思，但不能脫離詞根獨立生存，這點要特別注意，以免犯錯。
九年級英語上冊知識點：代名詞不出錯名詞的誤用，特別是代名詞的數和所指引的主語的數不符，使得後頭謂語動詞的.數也跟著出差錯，真是差之毫釐，失之千里，不可不察。
這裡要指出一些方向，以避免因代名詞的錯誤而使句子的意思模糊不清。
怎樣避免代名詞的錯誤呢?
㈠不要用同個代名詞指引兩個性別一樣的名詞，如：
① Mr Li told Mr Lin that he was wrong.
這裡的 he 既可指林先生，也可指李先生，含糊不清。應該改為 ②或③：
② Mr Li said to Mr Lin, "I am wrong."
③ Mr Li said to Mr Lin, "You are wrong."
㈡避免把代名詞和它所指引的名詞隔開太遠，如：
④ The man leaned over the bench for hours working on the plan. It was too low to be comfortable.
這裡的代詞 it 離開名詞 the bench 太遠，結果關係不清楚，因為在位置上，它更適合指引 the plan.在這種情況下，只好避開 it，而用名詞，即 the bench.
㈢避免濫用指示代詞“this, that”或關係代詞“who, which, that”泛指上文的內容。例如：
⑤ Tom's brother is an accountant, and this is the profession everyone envies."
這裡的 this 指“accountant”。“會計師”是一種專業人士，和後頭的“專業”(profession)並不相稱，因此要把 this 改為 accountancy(會計工作)，才合句子的意思。
⑥ The profit from the business was large, which I realised sometime later.
這裡的“which I realised sometime later”是句形容詞分句，應該出現在先行詞後面，不應該脫離出來而獨立。如果要用它來修飾全句話，更不合邏輯，應該改為⑦或⑧：
⑦ I realised sometime later that the profit from the business was large.(主句 + 名詞分句)
⑧ The profit from the business was large. I realised this (matter) sometime later.(單句 + 單句)
㈣避免用代名詞“they, you, it”影射腦子裡的事物，如：
⑨ In Singapore, it relies heavily on tourism as a source of national revenue.
這裡的 it 指向什麼呢?如果是心目中的“政府”或“旅遊促進局”，那就要明言，不要用不清不楚的 it：
⑩ In Singapore, the government……
In Singapore, the Tourist Promotion Board……
In less industrialised countries, they do not know the problems of urban development.
這裡的代名詞 they 是不是指 the people(人民)?如果是就用吧。In less industrialised countries, the people……過後，要再提這主語時，才用 they：……the people……They are only interested in their daily life.
其實，在這種主語不詳的情況下，被動語態是最好的選擇：
In less industrialised countries, the problems of urban development are not known.
九年級英語下冊知識點：被動語態的動詞
主動語態比被動語態直接而有力，多用主動語態，可以使文章充滿朝氣，呈現活力。在下列兩組句子中， (b)比(a)有力：
(1) first visit to New Zealand will always be remembered by me.
b. I will always remember my first visit to New Zealand.
(2) crowing of cocks could be heard at dawn.
b. The cocks' crow came with dawn.
雖然如此，在某些情況下，非用被動語態不可。前此已提過這事，這裡不再重述。這裡只有指出其中一點，就是有些動詞，如 "base, schedule, expect, suppose" 等，通常以被動語態形式出現。
例如：
(1)This survey was based on facts.
(2)The last train is scheduled to leave at 9pm.
(3)You are expected to come on time.
(4)All are supposed to work hard.
除了上述這些動詞之外，還有十種，幾乎都以被動式出現。
(一)有關“疾病”的動詞，如：
(1)Helen's left lung is infected.
(2)He is confined to the house by illness.
(3)The old man was seized with sudden chest pains.
(二)有關“疲乏”的動詞，如：
(4) I am completely exhausted after the game.
(5)Tom was done up after the race.
(三)有關“喜樂”的動詞，如：
(6)The children were fascinated by the toys.
(7)We were delighted to hear the good news.
(8) I am very pleased to see you here.
(四)有關“延遲”或“障礙”的動詞，如：
(9)The workers were held up by the heavy rain.
(10)The road was blocked by ice.
(11)The train was delayed by 30 minutes.
(五)有關“慣性動作”的動詞，如：
(12)Tom is addicted to smoking.
(13)Foreign workers are quite used to hard work.
(六)有關“煩惱”或“焦急”的動詞，如：
(14)Who was upset by John?
(15)Mother was annoyed to know this.
(七)有關“驚奇”或“震驚”的動詞，如：
(16) I was surprised to see him here.
(17)All were shocked to hear the bad news.
(八)有關“包圍”的動詞，如：
(18)The troops were surrounded.
(19)Troy was besieged.
(九)有關“沾汙”或“汙化”的動詞，如：
(20)Judy's reputation is tarnished.
(21)The water was contaminated with oil.
(十)有關“害怕”或“混亂”的動詞，如：
(22)All were frightened out of their wits.
(23)He was puzzled about what to do next.
要注意的一點是，上面這十類動詞有些已漸漸失去了動詞力量，轉化為慣用語。
