狼与狗那道题14000年应该是1,400年，但是答案好象没问题。
组题中的二维排列做好PP2的77、83和84即可，我还遇到比较繁的332分组，感觉和下面这道last的题类似，可以试试。
Eight new students-R, S, T, V, W, X, Y, Z-are being divided among exactly three classes-class 1, class 2, and class3. Classes 1 and 2 will gain three new students each: class 3 will gain two new students. The following restrictions apply:
R must be added to class 1.
S must be added to class 3.
Neither S nor W can be added to the same class as Y.
V cannot be added to the same class as Z.
If T is added to class 1, Z must also be added to class 1.
1.Which one of the following is an acceptable assignment of students to the three classes?
1 2 3
(A) R, T, Y V, W, X S, Z
(B) R, T, Z S, V, Y W, X
(C) R, W, X V, Y, X S, T
(D) R, X, Z T, V, Y S, W
(E) R, X, Z V, W, Y S, T
2.Which one of the following is a complete and accurate list of classes any one of which could be the class to which V is added?
(A) class 1
(B) class 3
(C) class 1, class 3
(D) class 2, class 3
(E) class 1, class 2, class 3.
3.If X is added to class 1, which one of the following is a student who must be added to class 2?
(A) T
(B) V
(C) W
(D) Y
(E) Z
4.If X is added to class 3, each of the following is a pair of students who can be added to class 1 EXCEPT
(A) Y and Z
(B) W and Z
(C) V and Y
(D) V and W
(E) T and z
5.If T is added to class 3, which one of the following is a student who must be added to class 2?
(A) V
(B) W
(C) X
(D) Y
(E) Z
6.Which one of the following must be true?
(A) If T and X are added to class 2. V is added to class 3. r> (B) If V and W are added to class 1. V is added to class 3. (C) If V and W are added to class 1. V is added to class 3. (D) If V and X are added to class 1. V is added to class 3. (E) If Y and Z are added to class 2. V is added to class 2. key:DEAECD verbal就不误导大家了，数学没什么好说的，只是题目难度好象没有什么梯度，所以最后出现极其简单的题比如my no.28居然是5(x+y)=5x+y, 问y和0大小比较（和以前有位G友一样），不要多想，影响下面就不好了，肯定800了。 GRE，过眼云烟，惟有压力下为了目标努力拼搏值得一生铭记和珍藏。更大的挑战没理由去拒绝！
