英文文法-助動詞

助動詞

助動詞是要幫助動詞表達不同的語氣,在結構上助動詞後面應接原形動詞。以下即精要地介紹關於助詞常考的重點:

 

1. 一般性的助動詞:a) shall與will表達“將要”(shall通常用於第一人稱I, we,而will則可用於任何人稱);b)can表達“能夠”,“可能”,“可以”,c)may表達“也許”,“可以”;d)must表達“必頇”、“一定”。

例:

1. My father could speak three languages. (能夠)

2. You have been working all day;you must be tired. (一定)

3. Mike might not be in the living room. (也許)

4. When she returns, she will telephone me. (將會)

 

2. 常考的助動詞句型:

a) 對目前事情的猜測,表達“現在也許”,“現在可能”用might+原形動詞或could+原形動詞,若是對過去的猜測,則用might+ have+ p.p.或could+ have+ p.p.;b)表達“現在一定是”用must+原形動詞,表達“過去一定是”則用must+ have+ p.p.,這種結構也是猜測,不過語氣很強;表達“目前應該這樣但並沒有這樣”用should+原形動詞,若表達過去則用should+ have+ p.p.。

例:

1. A:I can’t find my purse.

b):You could (might) have left it at home.

2. David passed the examination;he must have studied hard.

3. The phone is ringing;it could (might) be John.

4. The price is wrong;it should be $1000, not $1500.

5. They should have arrived here an hour ago, but they didn’t.

 

3. 其它重要的助動詞:

a) need:need可作助動詞,其結構為“need+原形動詞”,亦可作一般動詞,結構為“need to+原形動詞”,need若當一般動詞,則要考慮到第三人稱單數要加s。另外,need+ Ving表達“需要被‥”,請注意,這種結構一定是表達被動的意思。

例:

1. He needs to finish it as soon as possible. (一般動詞)

2. We needn’t hurry. (助動詞)

3. The patient needs taking care of. (需要被照顧)

4. The car needs repairing. (需要被修理)

b) mustn’t表“不可以”,needn’t表達“不需要”,“不必”

例:

1. It’s a secret;you mustn’t tell other people.

2. You needn’t come if you don’t want to.

c) ought to = should = be supposed to (應該)

例:1. People ought not to smoke in public.

2. You are supposed to get up early for the five o’clock train.

d) would rather:表達“寧願”,通常用的結構為“would rather A than B”,非常重要的是A與B要用原形動詞來帄行。

例:

1. I would rather drink tea.

2. I would rather walk than take a taxi.

e) had better+原形動詞:表達“最好‥”

例:

1. It’s getting dark;we had better leave.

2. You had better not be late.

f) used to+原形動詞:表達“過去習慣於”,若表達至今還存在的習慣則用be (get) used (accustomed) to+ Ving或NP。

例:

1. After dinner, Frank used to take a walk.

2. My grandfather is used to getting up early and doing exercise.

3. I expect we will get used to the busy life.

註:若“be used to”表達“被使用來‥”,則to為不定詞,應接原形動詞。

例:1. Wind can be used to produce electricity.

 

英文文法目錄

助動詞

英文文法-

主動被動

時態

動詞補語