Hi and Welcome to GMAT Club.
1. I can recommend that you get a copy of the GMAT Club grammar book. It’s designed for basic and pesky grammar topics focusing specifically on GMAT. It is mostly on target and doesn’t go beyond GMAT topics with the exception of the articles but I thought those would be valuable to include to make one a better communicator. You can skip it if you don’t want to cover it.
2. I would highly recommend reading a lot of quality English fiction and finding books that you like. Ideally this would be books you would read when you have some free time instead of watching TV or instead of mindlessly scrolling social media apps. Once you read about 1000 pages, you should start seeing improvement and you should start recognizing the things that sounds wrong to your ear. Basically your training your brain while having a good time enjoy a good book. You can look at my suggestions for books to read in the
gmat fiction post
3. Once you have some of the basics of the grammar down, or a lot of the basics, you can move on to more advanced things such as meaning and parallelism and more complex modifier things that are covered in the course.
4. Alternatively you can also purchase
Manhattan GMAT sentence correction book. You can get a sixth or fifth edition. It’s quite affordable. It is the gold standard of sentence correction but again it won’t have some of the basic grammar and if you did not like GMAT Club‘s grammar book, you can also pick up a copy of the Manhattan verbal foundations book. It’s quite helpful.
However, my personal opinion is that reading good quality fiction will give you an ear for mistakes and will make you better subconsciously which is the best possible solution. It won’t catch every mistake but it will take care of a lot of easy and medium questions
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