【文章內(nèi)容簡介】 be most likely to agree with the astronomers mentioned in line 13 about which of the following statements concerning the galaxy M87?A. The speed of the gas whirling around the center of M87 is caused by a dense object that is not a black hole.B. The concentration of mass at the center of M87 is probably a large cluster of dim stars.C. The presence of a black hole at the center of M87 is the most likely explanation for the speed of the gas whirling about the galaxy’s core.D. The speed of the gas whirling around the center of M87 is caused by a large concentration of mass at the core of M87.E. The gravitational influence of a star cluster would not be strong enough to account for the speed of the gas whirling around the core of M87.Q11: The passage asserts which of the following about the existence of black holes?A. Astronomers first speculated about the existence of black holes when they observed gas whirling around the center of a particular galaxy.B. Evidence used to argue for the existence of black holes is indirect, ing from their presumed effects on other astronomical bodies.C. Recent observations of certain astronomical bodies have offered proof.D. A considerable body of evidence suggests the existence of black holes, even though their behavior is not pletely consistent with the laws of physics.E. Many astronomers are skeptical about certain recent evidence that has been used to argue for the existence of black holes.Q12: Which of the following, if true, would most clearly undermine the possible explanation for the whirling gas in M87 that is mentioned in the last sentence of the first paragraph?A. The stars in a star cluster at the center of M87 could exert a strong gravitational force without tearing the cluster apart.B. A cluster of stars at the center would preclude the existence of certain other astronomical phenomena that have been observed at the center of M87.C. The stars within many existing galaxies, such as NGC 4258, are more closely spaced than are the stars within the core of M87.D. Only one other galaxy has been observed to contain gas clouds whirling about its center as they do about the core of M87.E. The gravitational force of a cluster of a billion or so dim stars would be sufficient to cause a whirling ring of gas and dust to collect around the center of a galaxy.13: GWD29Q2The discovery that Earth’s inner core rotates independently of and more quickly than Earth’s outer layers is responsible for advancing studies of the flow of heat from the inner through the outer planet and of the formation and periodic reversal in direction of Earth’s magnetic field.A. core rotates independently of and more quickly than Earth’s outer layers is responsible for advancing studies of the flow of heat from the inner through the outer planet and of the formation and periodic reversal in direction of Earth’s magnetic fieldB. core rotates independently of and more quickly than Earth’s outer layers is responsible for advancing studies of how heat from the inner core flows through the outer planet, and the formation and periodic reversal in direction of Earth’s magnetic fieldC. core rotates independently and more quickly than Earth’s outer layers are responsible for advancing studies of how heat from the inner core flows through the outer planet, and how Earth’s magnetic field forms and the periodic reversal of its directionD. core, rotating independently and more quickly than Earth’s outer layers, are responsible for advancing studies of the flow of heat from the inner through the outer planet, and the formation and periodic reversal in direction of Earth’s magnetic fieldE. core, rotating independently of and more quickly than Earth’s outer layers, is responsible for advancing studies of the flow of heat from the inner through the outer planet and of how Earth’s magnetic field forms and the periodic reversal of its direction14. GWD27Q14:The quality of early pieces of blown glass excavated in Italy and Western Europe by far surpass those of pieces from the eastern Mediterranean, when regarded not only in terms of the variety of shapes represented, but also in terms of decorative techniques and functionality.A. by far surpass those of pieces from the eastern Mediterranean, when regarded not only in terms ofB. surpasses by far those from the eastern Mediterranean, with regard not only toC. far surpass that of pieces from the eastern Mediterranean, not only regardingD. far surpasses that of the eastern Mediterranean, with regard to not onlyE. far surpasses that of pieces from the eastern Mediterranean, not only with regard to15: GWD29Q7Until a few centuries ago, any large bones discovered in the fields or caves of Europe, now known to be large prehistoric animals, were usually assumed to be the remains of giants and were often displayed as curiosities in castles, palaces, town halls, churches, and monasteries.A. now known to be large prehistoric animals, were usually assumed to beB. presently known as from large prehistoric animals, were usually assumed asC. bones now known to be those of large prehistoric animals, were usually assumed to beD. bones known at present as of large prehistoric animals, were usually assumed as those ofE. currently known as those of large prehistoric animals, were usually assumed to be those of16: GWD29Q8Which of the following, if true, provides eviden