Hi iamaditya1988,
I’m glad you reached out, and I’m happy to help. Let’s start with some good news: You studied for only 20 days and scored 30 points higher than you did on your most recent practice exams, so that's great! Also, a Q49 is a fantastic quant score.
Now for the less-desirable news: Your verbal score has ranged from 23 to 30, and as you stated, you need some major help in Sentence Correction. Also, as you correctly stated, there are “no shortcuts” to improving your GMAT score. Right now, it’s clear that you lack fundamental Sentence Correction skills needed for a high verbal score. So, the only move is go back and start with the foundations of Sentence Correction, and work your way to more advanced topics. I see that you want to take the test within a month. What deadlines are you aiming for?
Since you are looking for all the help you can get, I’m happy to provide some more detailed advice on how to improve your Sentence Correction skills. There are three aspects to getting correct answers to GMAT Sentence Correction questions: what you know, such as grammar rules, what you see, such as violations of grammar rules and the logic of sentence structure, and what you do, such as carefully considering each answer choice in the context of the non-underlined portion of the sentence. To drive up your Sentence Correction score, you likely will have to work on all three of those aspects. Furthermore, the likely reason that your Sentence Correction performance has not improved is that you have not been working on all three of those aspects.
Regarding what you know, first and foremost, you MUST know your grammar rules. Let's be clear, though: GMAT Sentence Correction is not really a test of knowledge of grammar rules. The reason for learning the grammar rules is so that you can determine what sentences convey and whether sentences are well-constructed. In fact, in many cases, incorrect answers to Sentence Correction questions are grammatically flawless. Thus, often your task is to use your knowledge of grammar rules to determine which answer choice creates the most logical sentence meaning and structure.
This determination of whether sentences are well-constructed and logical is the second aspect of finding correct answers to Sentence Correction questions, what you see. You have to develop your skill in seeing what is going on in the various versions of the sentence that can be created with the answer choices. To develop this skill, you probably have to slow way down. You won't develop this skill by spending under two minutes per question. For a while, anyway, you have to spend time with each question, maybe even ten or fifteen minutes on one question sometimes, analyzing every answer choice until you see the details that you have to see in order to choose the correct answer. As you go through the answer choices, consider the meaning conveyed by each version of the sentence. Does the meaning make sense? Even if you can tell what the version is SUPPOSED to convey, does the version really convey that meaning? Is there a verb to go with the subject? Do all pronouns clearly refer to nouns? By slowing way down and looking for these details, you learn to see what you have to see in order to clearly understand which answer to a Sentence Correction question is correct.
There is only one correct answer to any Sentence Correction question, there are clear reasons why that choice is correct and the others are not, and those reasons are not that the correct version simply "sounds right." In fact, the correct version often sounds a little off at first. That correct answers may sound a little off is not surprising. If the correct answer were always the one that sounded right, then most people most of the time would get Sentence Correction questions correct, without really knowing why the wrong answers were wrong and the correct answers were correct. So, you have to go beyond choosing what "sounds right" and learn to clearly see the logical reasons why one choice is better than all of the others.
As for the third aspect of getting Sentence Correction questions correct, what you do, the main thing you have to do is be very careful. You have to make sure that you are truly considering the structures of sentences and the meanings conveyed rather than allowing yourself to be tricked into choosing trap answers that sound right but don't convey meanings that make sense. You also have to make sure that you put some real energy into finding the correct answers. Finding the correct answer to a Sentence Correction question may take bouncing from choice to choice repeatedly until you start to see the differences between the choices that make all choices wrong except for one. Often, when you first look at the choices, only one or two seem obviously incorrect. Getting the right answers takes a certain work ethic. You have to be determined to see the differences and to figure out the precise reasons that one choice is correct.
To improve what you do when you answer Sentence Correction questions, seek to become aware of how you are going about answering them. Are you being careful and looking for logic and details, or are you quickly eliminating choices that sound a little off, and then choosing the best of the rest? If you choose an incorrect answer, consider what you did that resulted in your arriving at that answer and what you could do differently in order to arrive at correct answers more consistently. Furthermore, see how many questions you can get correct in a row as you practice. If you break your streak by missing one, consider what you could have done differently to extend your streak.
You also may find my article with more information regarding
how to score a 700+ on the GMAT helpful.
Feel free to reach out with any questions.
Good luck!