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。

a friend is a second self.

朋友乃第二个自我。

between friends all is common.

朋友间不分彼此。

friendship is a love without wings.

友谊是一种无形的爱。

a friend to all is a friend to none.

滥交者没有朋友。