What can we infer from Heather's mom's words?
A. People will know Heather's illness soon or later.
B. Heather doesn't want to accept chemo.
查看答案
Why does Heather's mother hope that the secret can be kept a little longer?
A. Because she doesn't want Heather to feel lonely all the time.
Because she doesn't want others to pay special attention to Heather.
当总效用达到极大值时，边际效用( )。
A. 达到最小
B. 达到最大
C. 为零
D. 为正
某消费者消费一个单位的某商品获得的效用为50，消费两单位该商品的效用为90，消费三单位的效用为121，则该消费者消费第三单位的该商品获得的效用边际效用为( )
A. 87
B. 40
C. 31
D. 71
下面( )是对物品的边际效用的正确理解。
A. 每增加(减少)一个单位的对物品的消费所引起的总效用的增(减)量
B. 最初增加的那个单位的消费所提供的效用
C. 消费一定数量的某种物品所获得总效用
D. 数学表达式为MU=－△TU／△Q
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