请教！各位

这道题看过一些讨论，但是还是不很明白。请教各位了，感谢之至！

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.

E?

我来大胆解释解释。原文的逻辑是：礼拜四发了５个；所有的在李百五发的是ＢＳ．　上礼拜有４个发去ＴＳ，其中三个是ＢＳ。这样推出一些结论：１。就是一个ｓｐｅｃｉａｌ　ｏｒｄｅｒ！也就是说这个ｓｐｅｃｉａｌ　ｏｒｄｅｒ必然发去别的地方了！２。因为ＴＳ里面有一个不是ＢＳ，而礼拜５的都是ＢＳ．因此那一个必然不是礼拜５发的。　也就是说只有Ｅ可以，其他的不是必要条件