GWD-26-37

Sound can travel through water for enormous distances, prevented from dissipating its acoustic energy as a result of boundaries in the ocean created by water layers of different temperatures and densities.

A.prevented from dissipating its acoustic energy as a result of

B.prevented from having its acoustic energy dissipated by

C.its acoustic energy prevented from dissipating by

D.its acoustic energy prevented from being dissipated as a result of

E.preventing its acoustic energy from dissipating by

答案是E，但是弄不懂它的结构preventing的逻辑主语是sound吗？声音阻止能量的消散吗？by boundaries ……是作什么成分？它又修饰哪个部分呢？有没有表被动的意思呢？