College classes vary tremendously. Some follow discussion formats while others follow lecture formats. Some are a mix of both.
College classes typically meet only three hours each week. That means a professor must cover significant amounts of material in a relatively short amount of time. Often, the focus for a professor is covering all the material that needs to be covered; the focus is not always on how well the student understands that material. Professors may lecture nonstop, expecting student to identify the important points and record them in their notes.
The most important thing is that students be focused, pay attention, listen attentively, and take notes in class. Students don’t have the luxury of tuning out. Being in a college class requires that the student be fully present mentally.
Professors typically say things once.