GRE出国考试的试题：GRE北美试题3

    Questions 18-22
    M, N, O, P, Q, and R are two sets of triplets, not necessarily in the order given. None of the six is married to a sibling or to someone of the same sex:
    Four of the six are male and two are female.
    Neither set of triplets contains three siblings of the same sex.
    M and P are married to each other.
    N is Q's only brother.
    18. Who CANNOT be sister and brother?
    (A) M and Q
    (B) O and R
    (C) P and Q
    (D) P and R
    (E) R and Q
    19. R must be a female if
    (A) M and Q are siblings
    (B) O and R are siblings
    (C) P and Q are siblings
    (D) O is P's sister-in-law
    (E) O is P's brother-in-law
    20. Which of the following statements must be FALSE?
    (A) O is P's sister-in-law.
    (B) Q is P's sister-in-law.
    (C) N is P's brother-in-law.
    (D) O is P's brother-in-law.
    (E) Q is P's brother-in-law.
    21. If Q and R are married to each other, which of the following must be true?
    (A) O is a male.
    (B) R is a male.
    (C) M is a female.
    (D) N is a female.
    (E) p is a female.
    22. If P and R are brother, which of the following must be true?
    (A) M and O are siblings.
    (B) N and P are siblings.
    (C) M is a male.
    (D) O is a female.
    (E) Q is a female.
    23. Recently a number of writers have proposed that our ancestors were influenced by visits from extraterrestrial and that these visitors were the builders of such monuments as the pyramids of Egypt.
    Which of the following statements, if true, would constitute the strongest evidence in support of the proposal described above?
    (A) The level of technology achieved by our ancestors who designed and built the monuments in question was actually much higher than it was formerly believed to be.
    (B) Monuments such as the pyramids of Egypt are very often positioned so that their prominent design features point to heavenly bodies.
    (C) Stories about beings from heaven appear in the mythologies of cultures that could have had no interchange with one another.
    (D) Modern builders cannot conceive of a way to duplicate the monuments without resorting to the most recent technological innovations.
    (E) Any extraterrestrial civilization advanced enough to have interplanetary space travel during the time of our ancestors could easily find means of communicating with them.
    24. To produce a pound of protein, herbivorous sea creatures such as abalones require relatively little plant food, whereas carnivores such as tuna feed on herbivores and thus require the conversion of thousands of pounds of plant food. Hence it would be better for ecological balance if people ate abalone instead of tuna.
    Which of the following, if true, is the best criticism of the argument above?
    (A) Abalone costs much more per pound than tuna does.
    (B) Tuna is much easier to harvest than abalone is.
    (C) Abalones mature so slowly that meeting market demands would exhaust the stock .
    (D) Human beings would require the same amount of protein from either abalone or tuna.
    (E) The average specimen of abalone is much smaller than the average specimen of tuna.          

    25.In an attempt to reverse the deterioration of the postal service in at least some respects, the government has raised the price of postage stamps. This effort will be effective since reducing the number of persons using the postal system should result in a corresponding reduction in the percentage of letter lost.
    The author of the passage above makes which of the following assumptions?
    Ⅰ. Fewer people will buy postage stamps if they are more expensive.
    Ⅱ. The percentage of letters lost by the postal service has been evidence of the deterioration of the postal system.
    Ⅲ. The government will improve the efficiency of the postal service with revenues from higher priced stamps.
    (A) Ⅰonly
    (B) Ⅱ only
    (C) Ⅲ only
    (D) Ⅰand Ⅱ only
    (E) Ⅰand Ⅲ only