modal: 법조동사(가능성·허락·의도 등을 나타내는 can·may·will 같은 조동사)
- During the war, the police might/ could may arrest you for criticising the government.
- 'I'm seeing Dr Evans next week.' 'That can't mustn't be right. He's on holiday then'
- I can't access the database. You must have to put in must have got to put in a password.
- Walking under a ladder is supposed to should be unlucky.
Advanced Grammar in Use 212p