prep题 答案是c， 但是想不通比较结构

106.       (30167-!-item-!-188;#058&004112)

Officials at the United States Mint believe that the Sacagawea dollar coin will be used more as a substitute for four quarters rather than for the dollar bill because its weight, only 8.1 grams, is far less than four quarters, which weigh 5.67 grams each.

(A) more as a substitute for four quarters rather than for the dollar bill because its weight, only 8.1 grams, is far less than

(B) more as a substitute for four quarters than the dollar bill because it weighs only 8.1 grams, far lighter than

(C) as a substitute for four quarters more than for the dollar bill because it weighs only 8.1 grams, far less than

(D) as a substitute for four quarters more than the dollar bill because its weight of only 8.1 grams is far lighter than it is for

(E) as a substitute more for four quarters rather than for the dollar bill because its weight, only 8.1 grams, is far less than it is for

选c      但我不清楚后面的far less than是谁和four quarters比？  还有这个比较结构在这里做什么成分？

会不会是

it（dollar coin） weighs only 8.1 grams, far less than four quarters。。。

less 用于修饰 it weighs。。。，即it weighs。。。，far less than。。。？

因为这里weigh后面跟的是数字，所以后面的quarters不会产生和8.1grams比较的歧义

Sacagawea dollar coin 和four quarters比较

这整个比较做8.1 grams的同位语