Used interrogatively, for what cause, with what motive, or for what purpose; on what account; wherefore.

(用作疑问词)为什么原因；有何动机；为何目的；何以；为何。

Used relatively, on account of which; for which.

(用作关系词)因以；因此。

A reason.

理由；原因。

Indicating the speaker's interest, sympathy, indignation, surprise, etc.

表示说话者之兴趣、怜悯、愤慨、惊讶之声。