知其所以然

"You ought to be able to explain why you're taking the job you're taking, why you're making the investment you're making, or whatever it may be. And if it can't stand applying pencil to paper, you'd better think it through some more. And if you can't write an intelligent answer to those questions, don't do it." Attogear QuickQuote Apps for iPhone/iPod Touch - http://www.attogear.com 发自我的 iPhone