Once you get behind, it can be a lot of work to catch up. If you don't understand something, chances are that others don't understand it either. You're doing both yourself and your classmates a favor when you ask questions. This allows me to know what your level of understanding of an idea is. Don't worry if your answer isn't perfect.
Any thoughtful answer is better than saying nothing.
If you need extra help, ask me. My office hours are noted at the beginning of this syllabus. If you cannot meet with me during these times, I will be happy to arrange an appointment with you at a time of mutual convenience. I'm more than pleased to help people on an individual basis, but if you have friends in the class who also could benefit from some help, arrange to see me as a group. If you need to get in touch with me between classes, call me at my office.