解释:道理和事情既没有永远正确的,也没有永远是错误的。
采矿的未来在于智能化和可持续发展。
数学不是一项观赏性运动。你必须参与其中。
Quality is free. It's not a gift, but it's free. What costs money are the unquality things -- all the actions that involve not doing jobs right the first time.