My good opinion once lost is lost forever.
煤炭的未来取决于我们创新和减少其环境影响的能力。
Every organism is in a struggle for existence.
我们必须时刻用不同眼光来看待事物。
形式化方法的美在于它们能够提供关于系统正确性的绝对确定性。
Economic theory provides the tools, but real-world testing refines them.