■本站特約作者 陳根花

從句中提出一種與客觀現實不相符或根本不可能存在的條件，主句會產生的一種不可能獲得的結果。條件句中的虛擬語氣根據不同的時間有三種不同的形式。

時間	從句謂語形式	主句謂語形式
將來	動詞過去式(be用were) should + 動詞原形 were to + 動詞原形	would / should / might / could + 動詞原形
現在	動詞過去式(be 用 were)	would / should / might / could + 動詞原形
過去	had +動詞過去分詞	would / should / might / could have + 動詞過去分詞

       2.  條件句中的虛擬語氣的舉例

(1) 將來時的條件句中的虛擬語氣。如：

If he should go to Qing Hua University, he would make full use of his time. 如果他要上清華大學的話，他就會充分利用他的時間了。

If he were to come here, he would tell us about it. 如果他要來的話，他會通知我們一聲。

(2) 現在時的條件句中的虛擬語氣。如：

If he were free, he would help us. 要是他有空的話，它會幫助我們的。

If he studied at this school, he would know you well. 如果他在這所學校學習的話，它會對你很熟悉。

(3) 過去時的條件句中的虛擬語氣。如：

If I had seen the film, I would have told you about it. 我如果看過這場電影，我會把電影內容告訴你了。

If I had got there earlier, I would have met Mr. Li. 如果我早點到那兒，我就會會到了李先生。

3. 運用條件句中的虛擬語氣時，須注意的幾個問題

(1) 當從句的主語為第三人稱單數時，謂語動詞若是系動詞be時，可用 was 代替 were。但在倒裝虛擬結構及 if I were you, as it were 中，只能用 were。如：

Were I ten years younger, I would study abroad. 要是我還年輕十歲的話，我會去國外學習。

If I were you, I would try my best to grasp the chance. 要是我是你的話，我要盡力抓住這次機會。