直述句
條件子句 主要子句
If + S. + 現在式V S. + shall/will/may/can + VR
*表示說話者認為if-子句中所陳述的假設，將來有可能實現。
If I have time, I will walk the dog in the park tomorrow.
If it _________(rain) tomorrow, they ______________(not come).
If we ____________(not hurry), we_______________(be) late.
假設語氣動詞使用原則
假設動詞用法 If- 條件子句中
動詞形式 主要子句中 動詞形式
與現在事實 相反
If I had wings, I would fly to anywhere that I wanted to be.
If he were rich, he would buy the house.
與過去事實 相反
I wouldn’t have gone to the meeting if you had told me that it was cancelled.
If he had studied hard, he could have won the scholarship.
與未來事實 相反
If the sun were to rise in the west, I would not change my mind.
If I should fail, I will/would do it again.
假設語氣其他句型 若非/要不是
But for + N.
= Without + N.
= If it were not for + N.
= But that + S + 現在式動詞
S. + would/should/could/might + 原形動詞
要不是你的幫助，他會失敗的。
如果沒有空氣的話，我們就活不下去了。
1. If the sun _____ rise in the west, David would marry Mary.
(A)does (B) has to (C) had to (D) were to
2. If you _______ speaking English every day, you’ll master it sooner or later.
(A)had practiced (B) practiced (C) practice (D) will practice 3. But for your advice, I _______ in the last attempt.
(A) would fail (B) fail (C) would have failed (D) failed
