表原因關系

1) for 判斷改錯： (錯) For he is ill, he is absent today. (對) He is absent today, for he is ill. for是竝列連詞，不能置於含兩個竝列分句的句子的句首，衹能將其放在兩個分句中間。

2) so, therefore He hurt his leg, so he couldn't play in the game.

注意： a. 兩個竝列連詞不能連用，但therefore, then, yet.可以和竝列連詞連用。 You can watch TV, and or you can go to bed. He hurt his leg, and so / and therefore he couldn't play in the game.

b. although… yet…，但although不與 but連用。 (錯)　Although he was weak, but he tried his best to do the work.. (對)　Although he was weak, yet he tried his best to do the work.