大全705，og49

705.The cameras of the Voyager II spacecraft detected six small, previously unseen moons circling Uranus, which doubles to twelve the number of satellites now known as orbiting the distant planet.

(A) which doubles to twelve the number of satellites now known as orbiting

(B) doubling to twelve the number of satellites now known to orbit

(C) which doubles to twelve the number of satellites now known in orbit around

(D) doubling to twelve the number of satellites now known as orbiting（B）

(E) which doubles to twelve the number of satellites now known that orbit

705, og-049, sec07-05

The pronoun which should be used to refer to a previously mentioned noun, not to the idea expressed in an entire clause. In A, C, and E, which seems to refer to a vague concept involving the detection of moons, but there is no specific noun, such as detection, to which it can refer. Also in E, the use of the phrasing the number... now known that orbit is ungrammatical and unclear. B and D use the correct participial form, doubling, to modify the preceding clause, but D, like A, uses known as orbiting rather than known to orbit, a phrase that is more idiomatic in context. B, therefore, is the best answer.

根据解释doubling是修饰整个句子的，可是我认为是修饰six small moons的，所以我认为用which更好。

请教这里怎么doubling修饰整个句子的说法？谢谢

valarie妹妹，我是这么认为的：

检查结果是数量的两倍，我觉得这个明显不符合gmat语法的，应该都是number与number比较，rate 与rate比较的，不是吗？

请大家继续讨论，谢谢！

double是个动词，而moon无法发出这个动作，只有cameras才能deteceted，也只有detection这个结果才能doubling；我们可以将句子理解为：这个发现说明卫星的数目是以前的两倍；

其次，指代moons在逻辑上和doubling不匹配，因为退一步说，这里只有6颗moons；而且，which后谓语的单数也决定了which根本不可能指代moons。

我想问一下为什么WHICH在非限定性从句中不能指代前面的整个句子?

If it is the moons that double the number and, as a result, "which" should be used to refer to them, "double" should be in its plural form, not "doubles". 

ETS has explained it clearly that we'd better use "which" to refer to a concrete noun mentioned before. In the case of refering to a clause, we should use a participle form. However, I don't know whether it's a common rule.