Learning makes a good man better and ill man worse.

好人越学越好，坏人越学越坏。

Learn not and know not.

不学无术。

Learn to walk before you run.

先学走，再学跑。

Let bygones be bygones.

过去的就让它过去吧。

Let the cat out of the bag.

泄漏天机。

Life is but a span.

人生苦短。

I cannot be your friend and your flatterer too.

朋友不能阿谀奉承。

If a man deceives me once, shame on him, if he deceives me twice, shame on me.

上当一回头，再多就可耻。