[求助]陈向东P37-8

arben

It has been hypothesized that much of the matter in the universe is  "dark",i.e.,unseen. Studies have shown that galaxies in many galaxy clusters are moving faster with respect to one another than they would if visible stars constituted all their mass. The studies suggest that the galaxies are moving under the gravitational influence of unseen mass in consilerable quantity.
Which of the following is an assumption underlying the passage above?
(A)Measurements of the speed of moving galaxies are extremely unreliable.
(B)The workings of gravitational forces are not particularly well understood.
(C)The aggregate mass of visible stars in the galaxies mentioned above can be estimated with some confidence.
(D)The general compoosition of unseen matter in the universe has been determined.
(E)Without exception,the galaxies mentioned above move toward one another.

答案C,为何?

deadendjy

这是个B-》A的题目，由Studies have shown that galaxies in many galaxy clusters are moving faster with respect to one another than they would if visible stars constituted all their mass

推出：The studies suggest that the galaxies are moving under the gravitational influence of unseen mass in consilerable quantity.

speed of galaxies with Visible mass > speed of galaxies with unseen => unseen mass effect galaxies moving 

根据A可行就有unseen mass 是可以测量的，就有Visible mass 怎么也要比unseen mass大，至于大多少不知道，但是有把握比unseen mass的大。

我这样想的，不知道大家怎么解读这个题目？