大全103 "be + twice" Thanks

[求助]请教大全103
103.American productivity is declining in relation to Europe’s; the energy expended per unit of production in the United States is as much as twice that expended in West Germany.
(A) as much as twice that expended in West Germany
(B) as much as twice that of West Germany’s expenditure
(C) up to two times of West Germany’s expenditure
(D) up to two times what West Germans expended
(E) up to double the West German expenditure
    答案是A

What is the function of "twice"?  I was confused by the structure "is as much as twice that ...."  Is "is +twice" correct?  Twice is a adverbial word.

NN help, Thanks

twice的用法可以参考这个：

The figure of seventy-million pounds was twice as big as expected.这里twice是副词。结构就是adv AS adj.

Thanks, Leeon.  I may get it.

Can I say that "twice" modifies "much"?  The stucture is "is + as much as + twice"?

Thanks again.

这个例子难道不是把twice放在as adj. as的前面吗? 但是这题的A项是说as adj. as twice....