How do I display the form data submitted by the php-HTML multi-choice control in PHP?

The following HTML form is submitted to recv. php: & quot; UserName: Sex: malefemaleauthorization Sion: StudentTeacherWorkerFavourite: fa php form html

The following HTML form is submitted to recv. php for display:

The recv. php code is as follows:

   '; Print_r ($ _ GET); echo'

';?>

1. Why can only one option be displayed in php even if multiple options, such as favorite, are obtained? How can I display all of them?
2. if multiple = "multiple" is added to the select statement, the drop-down list will not be displayed in one row but all. what is the problem? Don't I just want to turn it into multiple choices? What should we do?

Thank you!