According to scientists who monitored its path, an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, which brightened the Northern Lights and also possibly knocking out a communications satellite.
(A)an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic feld that surrounds Earth, which brightened the Northern Lights and also possibly knocking
(B)an expanding cloud of energized particles ejected from the Sun was what recently triggered a large storm in the magnetic feld that surrounds Earth, and it brightened the Northern Lights and also possibly knocked
(C)an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, brightening the Northern Lights and possibly knocking
(D)a large storm in the magnetic field that surrounds Earth, recently triggered by an expanding cloud of energized particles, brightened the Northern Lights and it possibly knocked
(E)a large storm in the magnetic feld surrounding Earth was recently triggered by an expanding cloud of energized particles, brightening the Northern Lights and it possibly knocked
题目分析：根据语义，我们知道划线外的it应该指代cloud（如果认为指代的是strom语义说不通），DE干掉。A用brightened和knocking，无法形成并列，干掉。B加了it，可是这几个动词发起者没有变，没必要加it，干掉。C用brightening和knocking进行对应，形成并列，并且没加代词，避免了前几个选项所犯的错误，这个选项一定对吗？不一定，但是只剩这个选项了，选呗。
