Prep2012-Pack1-SC-033 有没有大神路过。。。

sunyuwei

The infant mortality rate has decreased steadily over the past decades and is now at a lower rate than ever before.

A. now at a lower rate than

B. now lower than

C. now a lower rate than

D. presently lower than it was

E. presently lower than the rate was

这道题目别的问题点我都明白，除了D中的一个知识点  我表示有点迷糊 还请大神路过解答一下

D. The phrase ever before introduces a continuous expanse of time before the present moment (presently) that should be described with the present perfect tense it has been rather than the simple past tense of it was. Also the word order it was ever is the reverse of the more standard and less awkward it ever was.

红字部分这是什么知识点？ever before 难道不是作为一个表示时间的固定名词吗？我认为如果补出省略部分的话应该可以是 now lower than it has been ever  before,如果按照解释的话应该改成 now lower than it has ever been before?这是什么语言点?

sunyuwei

顶。。。。。。。。。。。。。

sunyuwei

顶顶顶。

solde

请教为什么要用完成时呢？

sunyuwei

solde 发表于 2014-10-6 18:57
请教为什么要用完成时呢？

完成时？没有划线的部分？因为是over the past decades==~~

solde

不是，是答案里面不是说如果不出谓语应该用完成时,这是为什么呢？

sunyuwei

solde 发表于 2014-10-6 22:48
不是，是答案里面不是说如果不出谓语应该用完成时,这是为什么呢？

因为时态一样时可以不补出，如果时态不一样就一定要补出，如果不补出，默认为与前面时态一致

solde

额。。。我其实是想问为什么这里要用完成时而不是过去时

DeliciaAn

solde 发表于 2014-10-7 18:20
额。。。我其实是想问为什么这里要用完成时而不是过去时

来自beatthegmat中GMATGuruNY，Mitch Hunt 的回复：
原帖子见：http://www.beatthegmat.com/gmat-prep-question-pack-comparison-t114457.html

Adverbs that refer to AN INDEFINITE TIME IN THE PAST (ever, never, already, yet) typically require the PRESENT PERFECT:

John is hungrier than he HAS EVER BEEN before.
My family HAS NEVER VISITED France.
Mary HAS ALREADY SEEN the movie.
Sally HASN'T FINISHED the book YET.

Thus, in D, WAS ever before is incorrect.

The OA implies the following:
The rate is now lower than [IT HAS] ever [BEEN] before.
The words in brackets are omitted, but their presence is understood.