这里的lighter或less可以作为一个排除的点吗？

(A) more… rather than 搭配错；its weitht 和后面 four quarters 比较对象不对等。(B) more as… than the dollar，the dollar 和前面比较对象有歧义。(C) 正确，介词短语 a substitute for… more than for…形式上并列。(D) more than 后面省略介词 for 使句子产生歧义；it 没有指代对象，根据句意 it 应该指 weight，不能 指代 its weight，因为原句是将 dollar 的 weight 和 for quarter 的 weight 进行比较，两个 weight 不同， 如果用 it 指代，则不符合逻辑。(E) more… rather than 搭配错；it 没有指代对象，根据句意 it 应该指 weight，不能指代 its weight， 原因同选项 D。

归因，分析错误
far...than后面是有省略的
D错在： it的同物指代，两次it指代不一样
dollar bill前没有介词for 不平行

Sth is lighter. Sth weighs less

B中than the dollar bill没加for或者be，容易有歧义，原句four quarters和dollar bill并列的

A——its weight和four quarters不平行

A.&E-This choice lack parallelism and is unidiomatic (more for X rather than for Y is incorrect). The correct comparison is more for X than for Y.
B&D.-By eliminating the "for" prior to "the dollar bill," This choice creates an ambiguity: Is the dollar coin being used more as a substitute for four quarter than for the dollar bill, or is the dollar coin being used more than the dollar bill as a substitute for four quarters?

BC区分：
因为more的位置，B的意思歧义，“ dollar coin作为 four quarters的替代品比作为dollar bill的替代品多“，但实际要表达的意思是” dollar coin作为 four quarters的替代品比作为dollar bill的替代品更合适“；
另外，后半句，是重量在比较，而不是两个主语（物体）在比较，所以用less不用light

q

A.&E-This choice lack parallelism and is unidiomatic (more for X rather than for Y is incorrect). The correct comparison is more for X than for Y.
B&D.-By eliminating the "for" prior to "the dollar bill," This choice creates an ambiguity: Is the dollar coin being used more as a substitute for four quarter than for the dollar bill, or is the dollar coin being used more than the dollar bill as a substitute for four quarters?

B, it weighs only 8.1 grams, far lighter than four quarters, 这里是主语和主语比较。
B的前面部分拆解开来就是：S was used more as a substitute for four quarters than as the dollar bill，这里要表达的意思是S是four quarters的替代品而不是dollar bill的替代品，它只能替代4个1/4美元的硬币，而不能替代美元钞票，因为纸币比S coin更轻。

C, it weighs only 8.1 grams, far less than four quarters, 这里是宾语和宾语比较，暗示four quarters拥有不同的宾语，ok

（转存）关于less和lighter我混淆了很久，这里摘录Ron的例句：
ron, who weighs 215 pounds, is heavier than his brother. --> CORRECT 人与人比
ron weighs 215 pounds, which is heavier than his brother. --> INCORRECT (pounds don't "weigh" anything; ron does) 重量与人比
ron's weight of 215 pounds is greater than his brother's weight. --> CORRECT 重量与重量比

8.1 grams 比较用less
its weight 比较用lighter
de ， 句尾it is for错误繁琐，都是weight，可以省略

B vs C， lighter vs less。
数字的比较，用more/less

A is use as B for C more than D,前面的句子有一个以上名词，被比较部分一定要补出谓语动词，如果是介宾结构里的名词被比较，则补出介词

de选项，句尾比较级不对等
because its weight, only 8.1 grams, is far less than it is for
注意前后的错误都要找

d.its weight 和it不对等
e.more...rather than错误

it weighs only 8.1 grams, far less than……，比较的是8.1 grams，用less
its weight of only 8.1 grams is far lighter than it is for……，比较的是weight这个东西，weight is lighter

数字用less/more比较 只有weight用lighter/heavier

a. because its weight, only 8.1 grams, is far less than four quarters. its weight和four quarters不对等
b. (8.1 grams) far less than four quarters比较不对等
d.its weight 和it不对等
e.more...rather than错误