单选题 The following data sufficiency problems consist of a question and two statements, labeled (1) and (2), in which certain data are given.You have to decide whether the data given in the statements are sufficient for answering the question. Using the data given in the statements plus your knowledge of mathematics and everyday facts (such as the number of days in July or the meaning of counterclockwise), you must indicate whether
Ａ. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Ｂ. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
Ｃ. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
Ｄ. EACH statement ALONE is sufficient.
Ｅ. Statements (1) and (2) TOGETHER are NOT sufficient.

单选题 Kara attends a university where students study for an average (arithmetic mean) of 13.4 hours per week. How many hours per week does Kara study? (1) The standard deviation of study time at Kara's school is 2.8. (2) Kara's study time is one standard deviation away from the mean.

【正确答案】 E

【答案解析】Statement (1) alone tells us more about the student population, but nothing in particular about Kara, so it is not sufficient and we can cross off A and D. Statement (2) alone tells us nothing because we don't know what the standard deviation is, so we can eliminate B. Together, the statements tell us that Kara studies for either 16.2 hours or 10.6 hours, but because we don't know whether she studies more or less than the mean, the statements are not sufficient together and our answer is E.

单选题 The cards in a deck are numbered consecutively from 1 to 20. If some cards are red and some cards are black, what is the probability of drawing a red card? (1) The odd-numbered cards are all red. (2) The even-numbered cards are all black.

【正确答案】 C

【答案解析】This is a very deceptive problem. Statement (1) tells us that 10 of the 20 cards are red, but it doesn't say that those are the only red cards in the deck, so it's not sufficient on its own and we can eliminate A and D. The same thing applies to statement (2); it doesn't say that those are the only black cards in the deck. When we put the statements together, on the other hand, we see the whole picture and know that exactly 10 of the 20 cards are red. So our answer is C.

单选题 One-fifth of the light switches produced by a certain factory are defective. Four-fifths of the defective switches are rejected and

【正确答案】 B

【答案解析】[解析] 根据题意可得出售的有缺陷的开关占总量的比率： [*] 出售的无缺陷开关占总量的比率： [*] 则出售的开关中有缺陷的开关所占的比例为： [*]

单选题 Consumers in California seeking personal loans have fewer banks to turn to than do consumers elsewhere in the United States. This shortage of competition among banks explains why interest rates on personal loans in California are higher than in any other region of the United States.
Which of the following, if true, most substantially weakens the conclusion above?

A. Because of the comparatively high wages they must pay to attract qualified workers, California banks charge depositors more than banks elsewhere do for many of the services they offer.
B. Personal loans are riskier than other types of loans, such as home mortgage loans, that banks make.
C. Since bank deposits in California are covered by the same type of insurance that guarantees bank deposits in other parts of the United States, they are no less secure than deposits elsewhere.
D. The proportion of consumers who default on their personal loans is lower in California than in any other region of the United States.
E. Interest rates paid by California banks to depositors are lower than those paid by banks in other parts of the United States because in California there is less competition to attract depositors.

【正确答案】 A

【答案解析】[解析] 本题读题重点也是段落最后一句话，其推理关系为缺乏竞争一贷款利率高，实际上，我们发现“缺乏竞争”是对“贷款利率高”的解释，暗含其是惟一原因。反对多用“有他因”的思路。(A)指出是由于加州的服务成本高而导致贷款利率高，所以(A)正确；(B)是在“personal loans”与“other types of loans”之间做了无关比较，且上面推理并未涉及“other types of loans”；(E)易误选，但(E)表明加州银行向储户支付的利率低，说明其成本低，但成本低应导致贷款利率低才对，这与“贷款利率高”的事实不符，而事实一般不能反对，所以(E)不对。

单选题 A digital wristwatch was set accurately at 8:30 a.m. and then lost 2 seconds every 5 minutes. What time was indicated on the watch at 6:30 p.m. of the same day if the watch operated continuously until that time?

A. 5:56
B. 5:58
C.6:00
D. 6:23
E. 6:26

【正确答案】 E

【答案解析】[解析] 从上午8点半到下午6点半，共经过了10个小时，所以根据题意可求出该手表在这10个小时中所慢的时间为：(10×60)÷5×2=240秒，该手表在10个小时内慢了4分钟，所以在下午6点半时，该手表上的时间是6点26分。

单选题 Many geologists theorize that the trail of volcanic craters and cinder cones along the Snake River plain of southern Idaho was produced as the North American continent slid westward over a stationary "plume," a vertical channel through which molten rock rose intermittently from the Earth's core to burst through its crust.
Which of the following, if true, tends to support the geologists' theory of how the trail was produced?

A. The largest craters and cinder cones are on the eastern margin of the trail.
B. The most violent volcanic activity apparently occurred at the western margin of the trail.
C. The craters and cinder cones are evenly spaced throughout the extent of the trail.
D. The newest craters and cinder cones are on the eastern margin of the trail.
E. The craters grid cinder cones on the western margin of the trail generally took longer to form than did those on the eastern margin.

【正确答案】 D

【答案解析】

单选题 What is the value of x²-y²?
(1)x+y=2x
(2)x+y=0

A. 条件(1)充分，但条件(2)不充分．
B. 条件(2)充分，但条件(1)不充分．
C. 条件(1)和(2)单独都不充分，但条件(1)和条件(2)联合起来充分．
D. 条件(1)充分，条件(2)也充分．
E. 条件(1)和条件(2)单独都不充分，条件(1)和条件(2)联合起来也不充分．

【正确答案】 D

【答案解析】[解析] 由(1)可得x-y=0，从而可以得出x²-y²=(x-y)(x+y)=0，所以(1)充分；由(2)也可得出x²-y²=(x-y)(x+y)=0，所以(2)也是充分的。

单选题 The senator has long held to the general printable that no true work of art is obscene and thus that there is no conflict between the need to encourage free artistic expression and the need to protect the sensibilities of the public from obscenity. When well-known works generally viewed as obscene are cited as possible counterexamples, the senator justifies accepting the principle by saying that if these works really are obscene then they cannot be works of art.
The senator's reasoning contains which one of the following errors?

A. It seeks to persuade by emotional rather than intellectual means.
B. It contains an implicit contradiction.
C. It relies on an assertion of the senator authority.
D. It assumes what it seeks to establish.
E. It attempts to justify a position by appeal to an irrelevant consideration.

【正确答案】 D

【答案解析】[解析] 本题重在思考(D)选项为什么正确以及体会此类题目选项所使用的语言。

单选题 At the company picnic, all of the employees who participated in more than four of the scheduled events, and only those employees, were eligible for the raffle held at the end of the day. Since only a small proportion of the employees were eligibly for the raffle, most of the employees must have participated in fewer than four of the scheduled events.
Which one of the following arguments exhibits a flawed pattern of reasoning most like that exhibited by the argument above?

A. Only third-and fourth-year students are allowed to keep cars on campus. Since one quarter of the third-year students keep cars on campus and one half of the fourth-year students keep cars on campus, it must be that fewer third-year students than fourth-year students keep cars on campus.
B. Only those violin students who attended extra rehearsal sessions were eligible for selection as soloists. Since two of the violin students were selected as soloists, those two must have been the only violin students who attended the extra sessions.
C. The only students honored at a special banquet were the band members who made the dean's list last semester. Since most the band members were honored, most of the band members must have made the dean's list.
D. All of the members of the service club who volunteered at the hospital last summer were biology majors. Since ten of the club members are biology majors, those ten members must have volunteered at the hospital last summer.
E. All of the swim team members who had decreased their racing times during the season were given awards that no other members were given. Since fewer than half the team members were given such awards, the racing times of more than half the team members must have increased during the season.

【正确答案】 E

【答案解析】[解析] 本题的推理犯了不严谨的毛病，不超过四个的补集是等于或少于四个，因此本题的结论应该是大多数雇员参加的预定节目的个数一定不超过四个。选项(E)很明显犯了与题干中的论述相一致的推理错误，它忽视了有一定数量的队员的比赛时间能保持不变的可能性。