Reading in advance will help us to understand more easily when the teacher in class. If my read do not understand myself, to ask teachers to understand really won't have a problem in the process.
Reading prior study will help us understand more easily when students at the teacher. Where, if I myself did not understand then asks the professor. To understand it will not be a problem in the exam.
Reading the book before the study will help us to understand more easily when studying when teaches. If what I read do not understand can ask the teacher. To really understand to be a problem during the exam.