One of the best question banks to practice

e-GMAT Verbal Scholaranium is very useful in order to practice and excel, and at the same time identify you weak areas.
It's divided into 3 sections-RC/SC/CR
Each section is divided into difficulty levels- Easy/Medium/Hard - It helps to know where you stand and how much effort is required.
All topics are covered.
You can take full length tests or customize the test according to the needs - this is very useful in order to test and improve any particular area.
Quizzes are saved and can be given as many times as you want - This can be helpful if you are making same mistakes again then you didn't get the concept and need to go back check that particular section.
Every question has an explanation and if any query can post on forum too.
On dashboard it shows your progress (as a whole and section wise too) and where you stand from accuracy point of view and timing. This can be very useful to have a benchmark to compare your own performance over the period.
In nut shell - must to have for non-natives ( best use with e-GMAT verbal course).