2. If you think the teacher is explaining too fast, you can mark the places you don't know well before asking the teacher after class.
3. If you think you don't know anything. Nothing is clear, this is the basic problem. Just consolidate and review from the foundation.
4. You can do related exercises after class. Only in this way can we master the main points skillfully.
LZ doesn't know what function he is learning. But no matter what function it is, it is the relationship between variables. So it is important to know the variables and definitions (although this is not used in the title). But because your mind has a new concept of function, you won't always think about why and why. Questions like this.