You can also ask questions through email, office hours, or in person. The review questions and sample test questions are designed to review the lecture and reading material. You probably won't see identical questions on the test, but the review questions give you a VERY good idea as to what topics I think are important. Remember, some of the question you see in the review sections ones I have used on tests in other years. It won't work.
Astronomy is a complex subject.
If you work a little every day, you will be able to understand the connections between the topics. If you don't keep up with the review questions and the reading, you won't understand these connections. It gives me a warm, fuzzy feeling inside when I know that someone is listening and wants some part of my lecture clarified. If you have trouble, consider getting a tutor. There are a number of student tutors available for Astronomy 105.