1. A home schooling management system requires the following functions. Tutors can register their information, modify their own information, browse tutoring information and search for tutoring information. Students who need tutoring services can register their information, modify their information, browse tutoring information and search for tutorinng information. Administrator can log in and register tutor information, publish website announcements and process tutor information. Draw the use case diagram of the system according to the requirements. 2. The posting system of a web forum has the following requirements. (1) Record the content of the post: the system checks the visitor's input, if there is no illegal content, save it to the post content file. Otherwise, The system prompts that the content is illegal. (2)Displays the content of the post: read the post content from the post content file and displayed on the screen in a certain format. Draw the data flow diagram of the subsystem