A true friend is one soul in two bodies.
挚友如异体同心。
 
A life without a friend is a life without a sun.

人生没有朋友，犹如人生没有了太阳。  

 
Be slow in choosing a friend; slower in changing.
择友亦慎，弃之更慎。


  
Everything is good when new, but friends when old.
物莫如新，友莫如故。


 

A hedge between keeps friendship green.
朋友间保持一定的距离可使友谊永存。


 
It is better to be alone than in bad company.
交恶友不如独处。