文法重點(三) ：條件子句與假設語氣
1. 條件句：表達「前提」或是「要件」，必須滿足要件才有後續，但是不確定事情會不會發生。在這樣的句型裡，if 和 when 可以互換
例句：If there is a typhoon coming, we will cancel the baseball game. (如果有颱風來，我們就會取消棒球比賽)
解析：不確定颱風來不來，但颱風來就不比賽。
例句：When you come to our school, I will show you around. (你來我們學校的話，我就帶你參觀一下)
解析：不知道你會不會來，來了就帶你參觀。
2. 與現在事實相反的假設句 If + S + were / Vpt , S + would / could / should + V
例句：If I were you, I would go. (如果我是你，我會去)
解析：事實上我不是你。
例句：If I had money, I would buy that house for you. (如果我有錢，我會買那間房子給你)
解析：但我沒有錢。
3. 與過去事實相反的假設句 If + S + had Vpp, S + would / could / should + have Vpp
例句：If I had studied hard, I would have passed the test. (如果我當時用功點，我就會通過考試)
解析：可惜當時不夠用功。
例句：If I had had time, I would have read the new series of novels. (如果當時我有時間，我就可以讀完最新系列的小說了)
解析：可惜當時沒有時間。
4. wish也是一種假設，用來表示願望。
(1) 永遠無法實現的願望
例句：I wish I could fly high in the sky. (但願我能飛在天空上)
解析：人類無法不借助外力飛翔，所以是永遠無法實現的願望。
(2) 過去沒有實現的願望 (通常表示一種後悔或是遺憾)
例句：He wishes he had not been there. (他希望自己從未到過那兒)