单选题 One's thoughts must be directed to the future, and to things about which there is something to be done. This is not always easy; one's past is a gradually increasing weight. It is easy to think for oneself that one's emotions used to be more vivid than they are, and one's mind more keen.
A. to things about which
B. a gradually increasing weight
C. think for oneself
D. one's mind more keen

【正确答案】 C

【答案解析】[解析] 本题中首句提到“一个人应当考虑未来”，据此可以推知C项是说“人们往往会暗自思忖，我过去感情多么丰富，思想多么敏锐，现在不行了”。think for oneself意为“自己作出决定”，因此这里应改为think to oneself“暗自思忖，心里想到”。