1. 用because引導:because是引導原因狀語從句最常用的連詞,其意為“因為”。如:
The little boy was crying because he was lost.
那小孩因迷路而哭。
I bought the house simply because it was large.
就是因為這所房子大我才買的。
2. 用as引導:as也可以用於引導原因狀語從句,意思是“由於”。如:
As he is ill, he can’t come to the meeting.
由於生病了,他不能來參加會議。
As you weren’t there, I left a message.
由於你不在那兒,我留了個信兒。
3. 用since引導:since引導原因狀語從句時,意思是“既然”。如:
Since you ask, I will tell you.
你既然問,我就告訴你。
Since you are going, I will go.
既然你去,我也去。
4. 用now that引導:now that引導原因狀語從句的意思也是“既然”。如:
Now that you have come you may as well stay.
既然你來了,你就留下。
Now that you’re growing up you must learn to stand on your own two feet.
你既然已經長大成人,就得學會獨立生活。
5. 習慣用法:不要受漢語意思影響將表示“因為”的連詞與表示“所以”的 so 連用。如:
■既然你很忙,那就不必來了。
誤:As you are busy, so you needn’t come.
正:As you are busy, you needn’t come.
正:You are busy, so you needn’t come.
as是從屬連詞,在此引導原因狀語從句;so 是並列連詞,在此連線一個並列句,所以誤句結構混亂,應去掉其中一個。
6.強調原因的.先行詞——because
無論在書面語還是口語中,because都是四者中最常見的一個(口語裡有時縮略為cos)。當我們強調原因時,通常使用because。另外,當because從句出現在句首時,後面要用逗號和主句分開。例如:
Because you're not burning calories, everything you eat turns to fat.
Everything you eat turns to fat because you're not burning calories.
你吃下去的東西都會變成脂肪,因為你沒有消耗能量。
7.強調結果的先行詞——as、since
當我們想要強調結果而非原因時,通常使用as或since。
Since/As we've got a few minutes to wait for the train, let's have a cup of coffee.既然火車還有幾分鐘才來,我們先喝杯咖啡吧。(強調的重點在於喝咖啡)
8.此外,for也可以表原因。例如He found it increasingly difficult to read, for his eyesight was beginning to fail. 需要注意的是for不能放在句首。