建筑始于工程结束之处。
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.
生活中最好的东西是免费的。
解析:教导学生,不到他想弄明白而不得的时候,不去开导他;不到他想出来却说不出来的时候,不去启发他。