LSAT-24-4-19

19.   Nearly all mail that is correctly addressed arrives at its destination within two business days of being sent. In fact, correctly addressed mail takes longer than this only when it is damaged in transit. Overall, however, most mail arrives three business days or more after being sent.

If the statements above are true, which one of the following must be true?

(A) A large proportion of the mail that is correctly addressed is damaged in transit.

(B) No incorrectly addressed mail arrives within two business days of being sent.

(C) Most mail that arrives within two business days of being sent is correctly addressed.

(D) A large proportion of mail is incorrectly addressed.（D）

(E) More mail arrives within two business days of being sent than arrives between two and three business days after being sent.

我觉得答案是A, 请NN分析一下.

D is certainly the correct answer.

A is incorrect.  A, "A large proportion of the mail that is correctly addressed is damaged in transit", plus "correctly addressed mail takes longer than this (two business days) only when it is damaged in transit", directly contradict with "Nearly all mail that is correctly addressed arrives at its destination within two business days of being sent."

谢谢两位NN, 我明白了.

doesn't hurt give it a shot~~~~~

must be true就是充分条件, 则有A就有B, 无B则无A

将D取非:

A large proportion of mail is correctly addressed.

由题干可知damaged mail是少数因为nearly all in 2 days

则应该是

Nearly all of the large portion arrives at its destination within two business days of being sent.

与most mail arrives three business days or more after being sent.相反

Pls correct me if I'm wrong.