prep1-239

239.
            (28502-!-item-!-188;#058&003082)     

Were it not for the fusion-powered heat and radiation that rush from its core, instead its own weight would cause a star to collapse

A. instead its own weight would cause a star to collapse

B. instead a star would have collapsed under its own weight

C. a star would have to be collapsing under its own weight

D. a star would collapse under its own weight

E. its own weight would have caused a star’s collapse

请问E有什么错？its不是指star吗？

谢

E是过去时的虚拟吧 感觉像是特指某个star

这句话里it做什么成份？