补充题96

LES

对于下题为什么选D，我很茫然，请教高手，烦请一并解释错误选项。谢谢！

96.         There is substantial evidence that certain forms of solar energy either now or within a few years will be economically competitive with conventional sources of heat and power.

(A) either now or within a few years will be economically competitive with conventional sources of heat and power

(B) will either be economically competitive with conventional sources of heat and power within a few years or are so now

(C) will be economically competitive with conventional sources of heat and power either now or within a few years

(D) either are now economically competitive with conventional sources of heat and power or will be so within a few years（D）

(E) are either now or will be within a few years economically competitive with conventional sources of heat and power

LES

太感谢了！jnlvo你实在是太厉害了。