243. Some scientists have been critical of the laboratory tests conducted by the Federal Drug Administration on the grounds that the amounts of suspected carcinogens fed to animals far exceeds those that humans could consume.

(A) far exceeds those that humans could consume

(B) exceeds by far those humans can consume

(C) far exceeds those humans are able to consume

(D) exceed by far those able to be consumed by humans

(E) far exceed those that humans could consume

by far 多用来修饰最高级

Choice E is best. The plural verb exceed agrees in number with its subject, amounts, and the phrase those that humans could consume conveys the intended meaning clearly and without unnecessary wordiness. In choices A, B, and C, the singular exceeds does not agree in number with its plural subject, amounts. Choices B and C omit the conjunction that _an omission that is grammatically acceptable, but in the case of this sentence diminishes clarity. In D, the use of the passive voice in the phrase those able to be consumed by humans is unjustified, as it increases wordiness while stating the meaning less precisely: it is accurate to call humans "able,' but not to call those [amounts] "able."

这个题目的答案没有问题

但是我奇怪的是，ETS为什么在解释中没有提到far 和by far的区别

我的感觉和记忆里

far修饰比较级

by far修饰最高级

请NN确认

一般都是副词修饰动词啊，区别就是一个在前，一个在后，如这里的A far exceeds B和A exceed B by far.

你说的这个区别能举个例子吗？

我记得我高中时候学过，但是我不能MAKE SURE我老师讲的是否是符合现代英语的

此外，LONGMAN上有例子

规律好象确实是by far修饰最高

far的感觉是much 的样子

我也觉得og怎么没说by far 和far的区别呢，by far 不是到目前为止吗，放在句子里意思不对啊，

难道by far有别的意思？

by far （adv.）+adj.

To the most extreme or evident degree:（“到目前为止”多用于修饰最高级）

She is by far the best executive in the company.

far adv.+adj.

To a considerable degree; much:（“相当的”多用于修饰比较级）

I felt far better yesterday.

by far有 by a large amount or degree的意思

longman里面的解释是：1、by far是固定搭配，used to say that something is much better, worse etc than anything else

2、by far（far是副词），有 by a large amount or degree的意思

有一个例句：

on the grounds that
 king金山soft
 prep.由于,以...为理由

on the grounds that the amounts of suspected ．．．而是做the laboratory tests 的定语从句

偶认为that the amounts of suspected carcinogens fed ..是做grounds的同位语

也不同意LS关于on the grounds that…介词短语作定语的说法, 个人认为是做状语修饰整个句子：be critical of sth. on the grounds that…

待讨论。。。