A fo may grow gray, but never good.

　　a fox may grow gray, but never good.

　　江山易改，本性难移。

　　a friend in need is a friend indeed.

　　患难见真情。

　　a friend is easier lost than found.

　　得朋友难，失朋友易。

　　a friend is never known till a man has need.

　　需要之时方知友。

　　a friend without faults will never be found.

　　没有十全十美的朋友。

　　'after you' is good manners.

　　“您先请”是礼貌。

　　a good beginning is half done.

　　良好的开端是成功的一半。

　　a good beginning makes a good ending.

　　善始者善终。

　　a good book is a good friend.