Kate,

The first time I took the GMAT I had a weak verbal score, so the second time around I used the MGMAT Sentence Corr. book and that helped a ton. I am sure the other MGMAT Verbal works are of the same quality. The GMAT forum also has some great study guides.

Good luck

Verbal is clearly your weakness. To that end, you may want to focus your studies on that for the time being since verbal weighs more heavily on your total score than does quant. A 44 score on quant is a decent enough showing, but that can also improved with effective study. If you are limited on time, I suggest just focusing on verbal. However, if you choose to do that, don't drop the ball on quant by ignoring it completely - you still want to keep your Q score up.

You mentioned you have already done MGMAT SC and the verbal in OG, but with a verbal score of just 23, there are some fundamental issues that you are probably struggling with. Is the vocabulary too difficult?

I noticed that you began all your sentences in your post in the form: "I am..., I studied.., I just..." Is the sentence construction of RC and CR too complex?

If you could provide us with more information about what you are truly struggling with in verbal, we may be able to provide better suggestions.

Thank you for your advices.
Yes, I think I have problems with fundamental sentence structures and
vocabs. When I went over Manhattan SC book, I felt like I understood the material on there. However, it didn't help me to apply those concepts to real questions.
Also, for Critical reasoning section, I do not have problem with logic, but is is hard to understand complex sentences for me. It is the same situation for R/C section.
What can I do to improve the score within 1 month?