The only real mistake is the one from which we learn nothing.
Children totally accept — and crave — family rules. “In our family we have a rule for X” is the only excuse a parent needs for setting a family policy. In fact, “I have a rule for X” is the only excuse you need for your own personal policies.
能源的未来在于平衡即时需求与长期环境目标。
The only defense against the world is a thorough knowledge of it.