條件語氣的動詞型態
Conditional Verb Forms

 


事實 vs. 非事實或假設

在表達一種條件的情況時,我們必須區分何者是事實的敘述,而何者是假設的敘述 (其他可表達假設意思的用語包括非事實、想像等)。例如,如果我們說

  • "The dog is always happy if Dad stays home."

這是現在事實的敘述。一般的真理也以相同的方式來表達:

  • "If the sun shines all day, it gets hot."

我們亦可以做過去事實的敘述:

  • "If we ate out at all, it was always in a cheap restaurant."

我們可以對未來做條件或假設的敘述:

  • "I will give you a call, if I fly to Phoenix tomorrow.

在未來式中,我們也可以使用其他語氣助動詞 -- may, might, could -- 再加原形動詞 (本例為 "give")。這些助動詞並非表示時間的現在、過去或未來,而是語氣上的變化。

假設的敘述:當我們要表達現在式的假設敘述時,有趣的是,我們係使用過去式動詞。

  • If you liked tennis, we could go play on the new courts.

  

(在這個句子中,我們也可以使用 wouldmight 來取代 could。) 即使說這個句子的人使用過去式的 "liked",但他並不是在說過去的事情。事實上,說話者是在暗示你不喜歡 (don't like) 網球 (現在的事實),所以現在也就不會有去新網球場打球的情況發生。

為了表達非事實、假設、猜測和想像 (這些語詞在條件語氣中指的都是相同的東西),英語採用一種有趣的方式,那就是將時間退後一步。這牽涉到兩個動詞:一是敘述條件的子句 ("if" 子句) 中的動詞,另一是結果子句中的動詞。現在讓我們來看看這些動詞如何變化。

如果結果子句是未來式,那麼我們就將條件子句的動詞退後一步,變成現在式

  • If the Bulls win the game tomorrow, they will be champs again.

現在非事實的事件而言,我們則將條件子句的動詞退後一步,變成過去式

  • If the Bulls won another championship, Roberto would drive into Chicago for the celebration.
  • I wish I had tickets.
  • If they were available anywhere, I would pay any price for them.
  • If he were a good friend, he would buy them for me.

注意:wish (希望,但願) 永遠是一種非事實的情況。再注意:be 動詞在非事實情況中都要變成 were 。等一下我們還會做更詳細的討論。

過去非事實的事件 -- 過去未發生,但我們可以想像的事情 -- 而言,我們再將條件子句的動詞退後一步,變成過去完成式

  • If the Pacers had won, Aunt Glad would have been rich.
  • If she had bet that much money on the Bulls, she and Uncle Chester could have retired.
  • I wish I had lived in Los Angeles when the Lakers were good.
  • If I had known you were coming, I would have baked a cake.

在最後一個句子中,請注意條件子句是使用過去完成式 (had known),而結果子句是使用條件語氣助動詞 + have + 主要動詞的過去分詞 (would have baked) -- 這是語氣助動詞的過去式寫法

若干寫作者似乎認為假設語氣正逐漸從英語中消失,但這可能是「非事實」。我們一直使用假設語氣來配合人類這種表達可能、假設和想像的需要。你可以溫習「動詞與動狀詞」中有關假設語氣的敘述,相信對你瞭解假設語氣會有所幫助。再提醒一次:在條件句中我們將 be 動詞改為 were 來表達假設語氣,這種假設語氣也是最常見的假設語氣。

  • If my brother were my boss, I wouldn't have a job today.
  • If I were to lose my job, I wouldn't be able to pay my bills. [注意:這句在語氣上比   "If I lose my job, I won't be able to pay my bills." 更不確定。]
  • If I were eight feet tall, I'd be one heck of a basketball player. [假設語氣有時在表達純粹想像的情況。]
  • If I should grow to be eight feet tall, I'd be a great basketball player. [這項敘述似乎更加天馬行空,更不可能。]

Would 和 Could

在表達非事實時,結果子句需要 would, could will。條件子句不使用這些助動詞 ;反之,條件子句的動詞在時間上較結果子句後退一步 (下面我們會以表格方式將它們的時式變化列出來,以方便讀者參考)。

未來條件語氣 VS. 假設條件語氣

當我們想要預測未來的條件事件 (我們認為可能發生的事情) 時,我們可以在 if 子句中使用現在式,而在結果子句中使用   willbe going to + 原形動詞。

  • If Jeffrey grows any taller, the basketball coach is going to recruit him for the team.
  • If he doesn't grow more, the coach will ignore him.

另一方面,假設條件語氣讓我們得以表達相當不可能或完全不可能的情況。

  • If I boxed against Evander Holyfield, he would kill me.
  • If my dad had been seven feet tall instead of less than six feet tall, he would have been a great athlete.

條件敘述的其他句型

條件句也可以主詞和動詞對調的倒裝法來表示。這一倒裝取代了 "if" 這個字;所以,在同一句子中同時使用 "if" 這個字以及主詞和動詞對調的倒裝是不對的。

  • Were Judita a better student, she would have a better relationship with her instructors.
  • Had Judita studied harder last fall, she would not have to take so many courses this spring.

條件句的各種時態

下列表格根據 if 子句中所表達的時間將條件句的用法分成三類:(1) 現在事實或未來事實或未來可能的事實;(2) 非事實或與現在事實相反;(3) 非事實或與過去事實相反。注意:條件子句的時間要退後一步。

現在事實
if 子句 獨立子句
現在的事實或常理
If + 主詞 + 現在式 主詞 + 現在式
If Judita works hard, she gets good grades.
未來事實
If + 主詞 + 現在式 主詞 + 未來式
If Judita hands in her paper early tomorrow, she'll probably get an A.
未來可能的事實
If + 主詞 + 現在式 主詞 + 語氣助動詞 + 原形動詞
If Judita hands in her paper early tomorrow, she may/might/could/should get an A.
現在非事實
if 子句 獨立子句
If + 主詞 + 過去式 主詞 + would/could/might + 簡單式動詞
If Judita worked this hard in all her courses, she would/could/might get on the Dean's List.
If + 主詞 + be 動詞 主詞 + would/could/might + 簡單式動詞
If Judita were president of her class, she could work to reform the grading policy.
過去非事實
if 子句 獨立子句
If + 主詞 + 過去完成式 主詞 + 語氣助動詞 + have + 過去分詞
If Judita had worked this hard in all her courses, she would not have failed this semester.

Guide to Grammar and Writing