【正确答案】 C

【答案解析】第一段第二句“Senior suggests that we need to redefine happiness：instead of thinking of it as something that can be measured by moment-to-moment joy，we should consider being happy as a past-tense condition”，意思是说我们应该把幸福看做为一种“过去时”的状态， 而不应该把它看做为一种可以即时即地的快乐。故答案为C。