问题
单项选择题
Most parents who are generous are good parents, but some self-centered parents are also good parents. Yet all good parents share one characteristic: they are good listeners.
If all of the statements in the passage are true, which one of the following must also be true
A．All parents who are good listeners are good parents.
B．Some parents who are good listeners are not good parents.
C．Most parents who are good listeners are generous.
D．Some parents who are good listeners are self-centered.
E．(E) Fewer self-centered parents than generous parents are good listeners.
答案
参考答案：D
解析： (A)指出“所有是好的听众的父母是好父母”，是“所有的好父母都是好的听众”的逆命题，逆命题与原命题不等价；(B)里的some推不出来；(C)“most”也推不出来；(E)为一新的比较，作为归纳必然不对，因此(D)是正确答案。