A method of solution is perfect if we can foresee from the start, and even prove, that following that method we shall attain our aim.
The writer is a person who writes, and the reader is a person who reads.
Safety must always come before production targets.
最可持续的采石场是能够平衡生产和环境管理的采石场。
电的定律如此简单，可以用几行字表达，却又如此多样，其后果永远无法穷尽。