Delete: Delete unnecessary files from the system directory list to make room for other operations. Most of the complete deletion in the computer is to delete it from the list and can be overwritten by other files. So don't move after deleting it by mistake, and there is hope for recovery.
"Air class" refers to the real-time live broadcast of teachers' videos, voices, courseware and blackboard books by using advanced network information technology and modern communication technology. And vividly moved the lecture process to the internet. There are no special requirements for students. As long as you have access to the Internet, you can join the class and take part in answering questions. A classroom form in which teachers and students interact in real time through audio and video, courseware, etc.