In mathematics, the most profound ideas often arise from the simplest observations.
No, not rich. I am a poor man with money, which is not the same thing.
人为某样东西实际支付的成本至少是标价的两倍,因为买来后设置、学习、维护、修理,以及最后处置,也需要耗费精力、时间和钱。不是所有的实际成本都在价签上。实际成本是标价的2倍。
Every genome is a unique historical document.