请教OG12-4

舟楫

Of all the vast tides of migration that have swept through history,“ maybe none is more concentrated as” the wave that brought 12 million immigrants onto American shores in little more than three decades.

(A) maybe none is more concentrated as
(B) it may be that none is more concentrated as
(C) perhaps it is none that is more concentrated than
(D) maybe it is none that was more concentrated than
(E) perhaps none was more concentrated than

答案是E
请教两个问题
1题目中的第一个句子of all。。。，在整句中起什么作用，是状语吗？
2时态问题，. OG解释说 the second part of the sentence uses the past tense verb brought,indicating that the event is over. the verb used in the comparative construction must also be past tense.请问怎么理解它的解释，过去时brought在修饰wave的从句中，为什么这个时态能决定主句用什么时态？那么为什么这道题要用过去时呢？
Thanks in advance

比莉

谢谢帖子帮助了17年的我~

cyanwang

受教了~~~

风飘月

学习了

ev0504

助动词应该是auxiliary verb

ninamikou

T0T 真经典的回答啊

Johnsonjz

如果没有特殊情况出现，比如有明确的时间状语，或者是客观现象、法律法规等，主从句的时态应该尽量保持一致

angelhxl

BAT太强大了，真是把所有的东西都融到一起了！！！好强大的解释！！！

superbat28

收个尾算了。。隔了这么多天，再回头看顿悟了。。
首先对比句应该是none +V more concentrated than the wave+ V. 而第二个谓语在本题中省略了，而省略的原则是第二个helping verb必须和第一个时态一致。

而又因为brought的因素，决定了那个wave已经完成，所以只能说 none was more concentrated than the wave was, 此时第二个was可以省略。 而不能是none is more concentrated than the wave is, 所以说none的动词必须是was！！！！

superbat28

up啊！