|
求助CR The axis of Earth’s daily rotation is tilted with respect to the plane of its orbit at an angle of roughly 23 degrees. That angle can be kept fairly stable only by the gravitational influence of Earth’s large, nearby Moon. Without such a stable and moderate axis tilt, a planet’s climate is too extreme and unstable to support life. Mars, for example, has only very small moons, tilts at wildly fluctuating angles, and cannot support life. If the statements above are true, which one of the following must also be true on the basis of them? (A) If Mars had a sufficiently large nearby moon, Mars would be able to support life. (B) If Earth’s Moon were to leave Earth’s orbit, Earth’s climate would be unable to support life. (C) Any planet with a stable, moderate axis tilt can support life. (D) Gravitational influences other than moons have little or no effect on the magnitude of the tilt angle of either Earth’s or Mars’s axis. (E) No planet that has more than one moon can support life.
答案是B我可以理解B是正确的，但是我当时选的是C，想不出来C有什么错误，感觉就是“Without such a stable and moderate axis tilt, a planet’s climate is too extreme and unstable to support life.”这句话的双重否定。所以肯定可以去双重否定，但是双重否定变成肯定就不正确了嘛？有人能解释下吗？谢谢！
| 
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2021-12-11 16:14:15
收藏
收藏
楼主