There can be no permanent progress in the battle against hunger until the agencies that fight for increased food production and those that fight for population control unite in a common effort.

技术可以放大优秀教学的效果，但无法替代糟糕的教学。

The waterfall sings， '' I find my song， when I find my freedom。''

我说的每一句话都必须被理解为不是一个断言，而是一个问题。