问一道GMAT逻辑题~The “Doppler effect” refers to the universally perceived change in the apparent pitch of a sound when that sound is approaching or receding from the listener.Specifically,whenever the distance between the listener and the s

问一道GMAT逻辑题~
The “Doppler effect” refers to the universally perceived change in the apparent pitch of a sound when that sound is approaching or receding from the listener.Specifically,whenever the distance between the listener and the source of the sound is decreasing,the sound will be perceived by the listener as higher than its true pitch; whenever that distance is increasing,the sound will be perceived by the listener as lower than its true pitch.If the distance between the listener and the source is not changing,the listener will perceive the true pitch of the sound.
If the above principle holds,which of the following should be observed as an eastward-traveling train is approached by a westward-traveling train that is blowing its horn?
\x05\x05\x05\x05\x05\x05A.Passengers in the eastbound train should hear the true pitch of the horn; passengers in the westbound train will hear a sound lower than the true pitch.
\x05\x05\x05\x05\x05\x05B.Passengers in the westbound train should hear the true pitch of the horn; passengers in the eastbound train will hear a sound lower than the true pitch.
\x05\x05\x05\x05\x05\x05C.Passengers in the eastbound train should hear the true pitch of the horn; passengers in the westbound train will hear a sound higher than the true pitch.
\x05\x05\x05\x05\x05\x05D.Passengers in the westbound train should hear the true pitch of the horn; passengers in the eastbound train will hear a sound higher than the true pitch.
\x05\x05\x05\x05\x05\x05E.Passengers in both trains should hear a sound that is higher than the true pitch.
为什么选D?解释一下题意和选项的意思吧

下面的回答完全害人.提干说的是多普勒效应,然后解释其内容.当声源跟听者的距离减少,听者听到的声音就会比真实的声音音调高.当声源跟听者的距离增加,听到的音调就低.如果距离没变,那么听到的就是真实的音调.问题是：一辆向东的列车与一辆向西的而且正在鸣笛的列车相遇,他们上面的听者听到的音调是怎样的.答案是：向西的那辆列车的乘客听到真实的音调,因为他们与声源距离没变.而因为向东的列车离向西的列车,也就是声源越来越近,所以听到的是更高的音调.希望可以帮到你.

题干：
向不拥有核武器的国家贩卖钚无疑是违反国际法的行为。然而如果美国公司不这么做的话，别国公司也会这么做的。
下面是抽象出其逻辑结构：
某种行为是违反法规的，但是你不做总有人做。前面的部分没有疑问了，就是某种行为不合适。后面的部分要体现出一定会有人做，实施者非此即彼。
A选项是说警察在某种情况下会这样做，这并没有说实施者非此即彼，而是说某些情况会做，某些情况下不会...

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题干：
向不拥有核武器的国家贩卖钚无疑是违反国际法的行为。然而如果美国公司不这么做的话，别国公司也会这么做的。
下面是抽象出其逻辑结构：
某种行为是违反法规的，但是你不做总有人做。前面的部分没有疑问了，就是某种行为不合适。后面的部分要体现出一定会有人做，实施者非此即彼。
A选项是说警察在某种情况下会这样做，这并没有说实施者非此即彼，而是说某些情况会做，某些情况下不会。
D是正入屋行窃违法，但是如果被告没做的话也会有人去那栋房子行窃的。这就是实施者非此即彼。
B和E是一样的，说总有些人做了违法违规的事，但没有非此即彼的概念在里面。
C说其实仔细看，被告案例并没有违法。这个显然不是。

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