【单选题】It is an astonishing fact that there are laws of nature, rules that summarize conveniently (1)_____ qualitatively but quantitatively-how the world works. We might (2)_____ a universe in which there ar...
【简答题】When your friends or family get married, there are all kinds of wedding etiquette and rules that govern their behavior. But did you know there are rules for wedding guests too? To ensure that you don’...