1. if引導(dǎo)條件狀語從句
If you mix yellow and blue, you get green.
你將黃色與藍色混合，便會得到綠色。
If she wants the servant, she rings the bell.
每當她需要仆人時，她便按鈴。
If I forget something, my mother reminds me of it.
每當我忘記了某件事情，我媽媽就會提醒我。
If he comes to the countryside, he sees his old friend.
如果他來鄉(xiāng)下，他總是來看他的老朋友。
2. if +not
We should do it with all our heart, if not we will leave it unfinished.
我們應(yīng)該全心全意地做這件事，不然的話，我們將會半途而廢。
I should go to school earlier, if not my teacher will criticize me.
我應(yīng)該早點上學(xué)，不然我的老師會責(zé)備我的。
He should tell me the truth, if not I will get angry.
他應(yīng)該告訴我真相，不然我會生氣的。
Mary should give me a call, if not she couldn't get the news.
瑪麗應(yīng)該給我打個電話，不然的話她就沒辦法得到這個消息了。
3. if引導(dǎo)讓步狀語從句
If she's poor, at least she's honest.
雖說她很窮，但至少她還是誠實的。
If I am wrong, you are wrong, too.
即使說我錯了，你也不對。
I'll do it, even if it takes me all the afternoon.
雖然會花費我一下午的時間，我還是要做這事。
I'll insist on doing it even if they scold me.
即使他們責(zé)怪我，我也會堅持做下去。
4. if作連詞，引導(dǎo)否定的條件狀語從句
If we are not healthy, happiness is impossible.
沒有健康，我們就不可能有幸福.
If he does not study hard, he will never pass the examination.
如果他不努力學(xué)習(xí)，考試就絕不會及格。
This baby seldom cries if he is not tired.
這個嬰兒很少哭，除非是累了。
If I do not understand what he says，I always ask him.
要是我不明白他所說的，就總是問他。