What way do you think it's the best for students to catch up the professor

I would say your best bet would be to speak with her after hours. Go to her office and politely tell her that she was speaking too quickly and could she please clarify what she said. This obviously works best if you have a good rapport with her already, but either way, I assume she'll be appreciative that you took the extra effort to get the lesson. You can also take the opportunity to ask her to slow down in future lessons. If your class is small, you could likely do this during class, but if your classes are larger, you have to make the extra effort. Good luck!

I hate when this happens. Sometimes, the professors talk too fast or too low that is impossible us to hear him. Any student asked her to talk slower? Usually, when this happens someone ask to the professor to he change the way he's talking.