Every discovery in science opens up a new set of questions, and that's what makes it so exciting.
金銀像其他商品一樣具有內(nèi)在價值,這不是任意的,而是取決于它們的稀缺性、獲取它們所耗費的勞動量以及生產(chǎn)它們的礦山所投入的資本價值。
過去是一個異國他鄉(xiāng);他們在那里做事的方式不同。
"Children's books should be both a mirror and a window."