如果你只是普通表达/陈述,用一般现在时,
如果是映射你自身,曾经发生的事情,也可以加入现在完成时的时态 (个人愚见,如有错,望指正)
所以上面说得都行,不过friendship在这里就不需要the的约束了
love comes and goes, only friendship lasts forever
or
Love has come and gone, only friendship has been be forever
Love has come and gone, only friendship has been lasting forever
现在完成进行时,表示将持续