Keep in mind that most answer choices
contain more than one grammatical error. Even if you can't pinpoint
a specific error in every choice, you can always eliminate some answer
choices by removing those with errors that you do recognize. Educated,
strategic guessing is far more helpful to your score than random, unstructured
guessing.
If you haven't already done so, reviewing
CAT's Grammar Module is a smart step to take.
Video Lessons and 10 Fully Explained Grand Tests
Large number of solved practice MCQ with explanations. Video Lessons and 10 Fully explained Grand/Full Tests.