How to prevent my mind from drifting off during lectures - Divisions by zero

I have weird quirk/tendency to stop listening / be distracted when someone explains something like during lectures for example. I fking hate this and it makes me dangerously close to failing college. Generally, I don’t have it elsewhere. Just when someone is doing a verbal explanation, online or in person. Perhaps it’s an issue of concentration, although generally I am able to do homework when I’m alone and focussing on it. At same time, I do get distracted relatively easily. What is wrong with me? How to force myself to pay attention during classes and not dose off?