[求助]请教GWD12(涛涛31之)-2O题

Q20:

Shipping Clerk:  The five specially ordered shipments sent out last week were sent out on Thursday.  Last week, all of the shipments that were sent out on Friday consisted entirely of building supplies, and the shipping department then closed for the weekend.  Four shipments were sent to Truax Construction last week, only three of which consisted of building supplies.

If the shipping clerk’s statements are true, which of the following must also be true?

1. At least one of the shipments sent to Truax Construction last week was specially ordered.
           
2. At least one of last week’s specially ordered shipments did not consist of building supplies.
           
3. At least one of the shipments sent to Truax Construction was not sent out on Thursday of last week.
           
4. At least one of the shipments that were sent out on Friday of last week was sent to Truax Construction.
           
5. At least one of the shipments sent to Truax Construction last week was sent out before Friday.

   Answer: E

给的答案是E,没怎么懂这题的答案是如何分析出来的...谢谢大家发言哦~~~~~

说一下，自己的想法不一定对，请各位指教

因为friday推出building supplies，所以逆否是可以的，就是至少一艘不是friday的,但是逆命题就不一定对了

呵呵，不晓得对伐

 Four shipments were sent to Truax Construction last week, onlythree of which consisted of building supplies.说明有一艘不是周五送的，因为all of the shipments that were sent out on Friday consisted entirely of building supplies,　而且the shipping department then closed for the weekend，所以只能是周五之前了；Ａ不对，有可能还有其他种类；Ｂ文中没提到；Ｃ不对，有可能４艘都是周四.文中只说 five specially ordered shipments 在周四送出,并没有说周四只送了这些; D也不对, 有可能都是周五以前送的, 文中并没有说只有周5才送building suppliers.