I am a final year student at a T1 nlu. In most subjects, they don't teach every section in classroom. However, it is always encouraged that students read all sections on their own and clarify their doubts with professors. If someone has attended all the classes for a particular course, that's enough preparation for them to score decent in the exam.
Exams are majorly application based, with little or no theory based direct questions. So, a good knowledge of sections and important case laws makes you good to go in the exam.
Nobody will teach you every section of every act. The more important things you learn are the principles and methods, so that when you are presented with a problem you know where to look and how to look. So yes you will learn the important sections and cases, but also how to usethem.
How are we tested in exam ?
Exams are majorly application based, with little or no theory based direct questions. So, a good knowledge of sections and important case laws makes you good to go in the exam.