question 1. Introduce the shortcut key
(F 8): debugging step by step. What are the special features and scenario applications
(F7): what"s the difference between step-by-step debugging and F8 functionality? What is the special function and scene application
(alt+shift+F7): you can also debug step by step, as if you can skip the whole loop, and what special function and scenario application
(shift+F8): it feels like ending the function function, but it can only end the loop or function, etc. What other special functions and scene applications want to tell you.
(alt+F9): it should be run directly to the mouse position.
(F9): code reset, F9 seems to reset debugging, but some people on the Internet say that it doesn"t work when I try to debug the next piece of code.
what"s the difference between the above six debugging? In particular, I feel no difference between the first two. Hope that kind-hearted people will be introduced through typical code examples and screenshots. Thank you.

question 2. (alt+shfit+F7) the button is grayed out and cannot be used. Why? This function should be able to reverse debug the code.

question screenshot:

read a lot of answers on the Internet are not ideal, I hope here can give me a good explanation, thank good people for good rewards.