aaba
@GMATNinjaTwo,GMATNinja,@mikemcgarry, pls help me with this question, the topic has been locked. There are similar questions that compare the time period, but in this question, D is incorrect, OA is E. WHy?
Never before had the e-business industry faced as many financial losses and employee cutbacks as they had in the late 1990s.
a. faced as many financial losses and employee cutbacks as they had
b. had to face as many financial losses and employee cutbacks as they had
c. faced the financial losses and employee cutbacks as they had faced
d. had to face as many financial losses and employee cutbacks as
e. faced as many financial losses and employee cutbacks as it faced
I checked on this question, and there's no source listed for it -- and it almost certainly is not an official GMAT question. And that's probably why the thread was locked: if the question is not from a reputable source, then we really don't want hard-working test-takers wasting their time on it.

The question seems to be an attempt to mimic this classic OG question:
https://gmatclub.com/forum/qotd-in-no-o ... l#p1963042. If you're clear about what happens in the official question, you're all set.
chesstitans
GMATNinja,
carcass. I believe your replies are great.
Nevertheless, since I am an international student, and idiom is sth that I barely know, I do not know how I improve my idiom skill.
Situation 1: if I sign up a gmat prep course, how do I know that I learn enough idiom from the prep course?
Situation 2: given that I have complete ESL 6, how do I check what idiom I still do not know?
There really is no such thing as "idiom skill", unless you're talking about English skills in general. Again, there are 25,000 idioms in English, so your knowledge of idioms will naturally accompany better English skills. If you read a lot of high-quality texts English, you'll get better at EVERYTHING in English -- including idioms. If you have tons of time on your hands, I suppose that you could try to memorize some of the lists that are out there, but as I've said repeatedly, I think memorizing idioms is a painfully inefficient way to improve your SC results.
In general, knowledge of idioms correlates very strongly with your fundamental reading skills in English. So if you struggle to understand RC and CR passages in general, odds are good that you also struggle with idioms, and vice-versa. It's not sexy, but the only realistic way to get better at both reading and idioms is to read more high-quality texts.
There are a couple of great GMAT Club threads on reading materials if you're taking a long-term approach to improving your verbal skills. Some wise Ukrainian guy wrote this classic post about books:
https://gmatclub.com/forum/books-to-rea ... 76079.html. And a charming Italian fellow wrote this one about periodicals:
https://gmatclub.com/forum/the-best-rea ... l#p1232840. Both of the gentlemen who wrote those posts are non-native speakers, and have been through exactly the same thing you're experiencing.
I hope this helps!