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
