Instruction
reference the following videos:
1. https://www.youtube.com/watch?v=-SgkLEuhfbg&feature=youtu.be
2. https://www.youtube.com/watch?v=OhwXk6byLC8&feature=youtu.be
Please write down the question first, and answer it before moving on to the next questions.
For the last question, please use the uploaded file.