The value of true friendship is seldom realized until it is lost.

友谊的真正价值很少能意识到，直到失去了。

youdao

True friendship is like health, the value of it is seldom known until it is lost.

真正的友谊犹如健康，失去之后才知其价值。

youdao

Sincere friendship like health, the value of which is seldom known until it is lost.

真诚的友谊好象健康，失去时才知道它的可贵。——歌尔登。

youdao

Given Mongolia's tradition of nomadic herding, it is not difficult for these children to be passed from one relation to another, until the parents have lost touch with them.

ECONOMIST: The street children are the symptom of a bigger problem