表示因果关系的并列连词。

主要有 for(因为), so(因此)等。如：

He shook his head, for he thought differently. 他摇了摇头，因为他有不同想法。

He told me to do it, so I did it. 他让我这样做，于是我就这样做了。

The child had a bad cough, so his mother took him to the doctor.

这孩子咳得很利害，所以他妈妈带他去看医生。

You are supposed to get rid of carelessness, for it often leads to serious errors.

你们一定要克服粗枝大叶，因为粗枝大叶常常引起严重的错误。

注意：for表示结果通常不能放句首，也不能单独使用。