问一道阅读题：阅读36套---Exercise13

fayehyfUID: 3476681

According to astronomer S.A. Phinney, kicking a rock hard enough to free it from Earth's gravity would require a meteorite capable of making a crater more than 60 miles across. Moreover, even if Earth rocks were freed by meteorite impact, Mars's orbit is much larger than Earth's, so Phinney estimates that the probability of these rocks hitting Mars is about one-tenth as great as that of Mars's rocks hitting Earth. To demonstrate this estimate, Phinney used a computer to calculate where 1,000 hypothetical particles would go if ejected from Earth in random directions. He found that 17 of the 1,000 particles would hit Mars.

Which of the following, if true, would cast most
doubt on Phinney's estimate of the probability of
Earth rocks hitting Mars?
○A Rather than going in random directions, about
25 percent of all particles ejected from Earth
go in the same direction into space.
○B Approximately 100 meteorites large enough to
make a noticeable crater hit the Earth each year.
○C No rocks of Earth origin have been detected
on Mars.
○D The velocity of rocks escaping from Earth's gravity is
lower than the velocity of meteorites hitting the Earth.
○E No craters more than 60 miles across have
been found on Mars.




答案是A
如果是这样，这个逻辑也太简单了啊！！！而且这篇文章我真的没看懂唉，火星的直径在这里面到底有什么关系？

浑浑之水UID: 3372111

这篇我记得我自己是用排除法做的
LZ是截文章的还是直接复制的？这篇文我记得有阅读，稍等我找找全文可能就能看懂了...

浑浑之水UID: 3372111

居然是短阅读= =
记忆偏差了，还以为是长阅读，读完就能懂了...
even if Earth rocks were freed by meteorite impact（前面有说其实不太可行因为会造成大的crater）， Mars’s orbit is much larger than Earth‘s,轨道越大概率越小~
火星直径在哪里OTZ
原文：
Recently some scientists have concluded that meteorites found on Earth and long believed to have a Martian origin might actually have been blasted free of Mars‘s gravity by the impact on Mars of other meteorites. This conclusion has led to another question： whether meteorite impacts on Earth have similarly driven rocks from this planet to Mars.
    According to astronomer S. A. Phinney， kicking a rock hard enough to free it from Earth‘s gravity would require a meteorite capable of making a crater more than 60 miles across. Moreover， even if Earth rocks were freed by meteorite impact， Mars’s orbit is much larger than Earth‘s， so Phinney estimates that the probability of these rocks hitting Mars is about one-tenth as great as that of Mars’s rocks hitting Earth. To demonstrate this estimate， Phinney used a computer to calculate where 1，000 hypothetical particles would go if ejected from Earth in random directions. He found that 17 of the 1，000 particles would hit Mars.