There will be seven performers in a talent show: a guitarist, a hypnotist, a juggler, a magician, a pianist, a singer, and a ventriloquist. Exactly three of the performers—the guitarist, the pianist, and the singer—will each require a recorded musical accompaniment. The schedule for the show has seven consecutive time slots. Each of the seven performers will appear in exactly one time slot, and each time slot will have exactly one performer appearing in it. The schedule must follow the rules below:　

 
　　The juggler must appear first.

　　The ventriloquist cannot appear immediately after the magician.

　　At most two performers requiring a recorded musical accompaniment can appear　in succession.

　　Which of the following is an acceptable schedule for the last four performers in the show¡

　　Fourth Fifth Sixth Seventh

　　Juggler Hypnotist Guitarist Pianist

　　Guitarist Magician Ventriloquist Singer

　　Magician Pianist Singer Guitarist

　　Singer Guitarist Pianist Hypnotist

　　Ventriloquist Hypnotist Magician Singer

　　答案：(E)

　　这是一道非常简单的排列题，但是分析题在于你会不会做，而在于你花了几分钟把它做完，在于速度。我们通过讲解几道题来体会一下如何迅速定位答案。

　　读题：7个表演者g,h,j,m,p,s,v参加表演，其中3个g,p,s有音乐伴奏。有7个位置，一人一个。

　　写条件：

　　1、j=1 (表示j在第一个位置)

　　2、～mv (表示v不能出现在m的后面)

　　3、～(gps) (表示需要音乐伴奏的3人中最多只有2人连续)

　　条件总结：

　　**注意g.p.s为等价元素（当然，如果在问题中又出现新的限制条件后，就不一定是）

　　If the ventriloquist appears third, the singer appears fifth, and the pianist appears sixth, which of the following must be true¡

　　The guitarist appears second.

　　The guitarist appears fourth.

　　The hypnotist appears second.

　　The magician appears fourth.

　　The magician appears seventh.

　　答案：(A)

　　If the singer appears third and the pianist appears fourth, the guitarist must appear either first or second

　　second or fifth

　　second or seventh

　　fifth or sixth

　　sixth or seventh

　　答案：(E)

　　If the ventriloquist appears fifth and the hypnotist appears sixth, which of the following must be true¡

　　The guitarist appears either third or seventh.

　　The magician appears either second or third.

　　The pianist appears either second or fourth,

　　The singer appears either second or seventh.

　　The singer appears either third or fourth.

　　答案：(B)

　　如果v=5，h=6，下面哪一个一定正确？

　　解题步骤：

　　1、v=5，条件2：～mv，∴m≠4，

　　2、扫一下选项，选项中都是元素在哪些位置，还剩4个元素，m,g,p,s, g,p,s为等价元素,所以g,p,s的位置只可能为 can be true, 不可能must be true？因此涉及gp，s的都不正确。只有B正确。当然也可用常规方法做，得到m≠4后，还剩4个元素，m,g,p,s, 还有一个条件没有用,～（gps），因此g,p,s不可能占据2,3,4三个连续位置，必有一个在7，m就必须在2/3

　　1 2 3 4 5 6 7

　　j v h

　　If the hypnotist appears sixth and the magician appears seventh, who of the following must be true¡

　　The ventriloquist appears third or fourth.

 
　　The singer appears fourth or fifth.

　　The juggler immediately precedes the pianist.

　　The pianist immediately precedes the guitarist.

　　The singer immediately precedes the hypnotist.

　　答案：(A)

　　如果h=6，m=7，下面哪一个一定正确？

　　解题步骤：

　　1、选项中涉及都是具体位置信息，g,p,s为等价元素，只剩下元素v，答案马上定位到A

　　2、常规方法，4个元素g,p,s,v, 一个条件～(gps)，所剩位置是2，3，4，5，为使它们不能连续，v绝对不能放在两头2/5，v只能放中间3/4。