能在两个月内重复出现。（条件全） 火凤凰：感谢网友ly018383的考证 Yorkton s city council has six members. Three members - Ford, Gonzalez, and Isaacson - represent
northern Yorkton, and three members - Kramer, Lee, and Marek - represent southern Yorkton. All six
will serve as members of the council for the year beginning January first. The president of the
council to serve a one-month term, beginning the first of each month, according to the following
conditions:
The presidency must alternate between the members form northern Yorkton and the members from
southern Yorkton.
Only one member can serve as president at a time.
No one serving a term as president can serve another term until every other council member has
served as president in the interim.
A member representing morthern Yorkton will be president in January.
1. Which of the following is a complete and accurate list of all of the council members who could
serve as president of the council in August?
(A) Ford, Marek
(B) Isaacson, Kramer
(C) Ford, Kramer, Lee
(D) Kramer, Lee, Marek
(E) Gonzalez, Kramer, Lee, Marek
2. Which of the following must be true?
(A) Ford is president of the council immediately after Marek is president.
(B) Ford is not president of the council in May or in July.
(C) Gonzailz is president of the council in January.
(D) Lee is president of the council in exactly one of the months February, April, or June.
(E) Marek is president of the council in exactly one of the months February, April, or May.
3. If Isaacson is not president of the council in March, which of the following must be true?
(A) Ford or Gonzalea is president of the council in September.
(B) Ford or Isaacson is president of the council in August.
(C) Kramer or Lee is president of the council in September.
(D) Lee of Marek is president of the council in August.
(E) Lee or Marek is president of the council in October.
4. If Gonzalez, Marek, and Ford are president of the council in January, February, and March, in
that order, which of the following must be true?
(A) Ford is president of the council in July.
(B) Ford and Kramer are president of the council in August and September, respectively.
(C) Gonzalez and Ford are president of the council in July and August, respectively.
(D) Kramer and Lee are president of the council in April and June, respectively.
(E) Marek and Ford are president of the council in August and September, respectively.
key: D; D; A; E
2、 记得一道，9中选7，p：2e，2m；q：1e，2m；r:1e,1m。 要求：1，>=3e 2,p,q,r中每个至多取3个。 感谢网友blueye的考证 Out of nine nominees, seven will be selected to form a committee. Exactly four of the nine nominees―two women and two men-belong to party P; another three―one woman and two men―belong to party Q, and the remaining two-one woman and one man― belong to party R. The rules governing the selection of the committee are as follows：
At least three women must be selected. No party can have more than three of its members selected.
16.Which of the following is an acceptable committee? Party P Party Q Party R (A) 1 woman --- 1 woman 2 men 2 men 1 man (B) 2 women --- 1 woman 1 man 2 men --- (C) 2 women 1 woman ---
