Studying is not just attending class everyday, listening, doing your homework and doing well during exams. Students are also required and are encourage to actively participate during class discussion. Lectures are not lively and are often vague if no discussion was made after them. And of course, you can not get very good grades if you are not participating to your class discussion because participation is included in overall grade computation.
There are students who actively and eagerly participate in every discussion but there are much more students who are hesitant to participate. And if you belong to the latter group, it’s time to help yourself because being timid in class is not good. You are losing the opportunity to express yourself and get even higher grades.
Don’t be ashamed to speak out especially when you know the answer or when you have something to ask. Remember that students who are participating in the answer and question part of their lectures are the ones that are easily remembered by professors. And professors tend to be more considerate and approachable to those students whom they knew better.
But of course, participate with sense; by answering appropriately or asking questions that are only related to what is being discussed. Never talk too much because it may you give negative impression.