The tears of the world are a constant quantity. For each one who begins to weep, somewhere else another stops. The same is true of the laugh.

The best teacher is the one who suggests rather than dogmatizes, and inspires his listener with the wish to teach himself.

The way positive reinforcement is carried out is more important than the amount.

Some people go to priests; others to poetry; I to my friends.

跨国合作对解决全球粮食问题至关重要。