Modal Verbs Usage

Front

can

Back

What does 'expressing ability or possibility' refer to?

Front

can (informal) / may (formal)

Back

What is the purpose of 'asking for permission'?

Front

can

Back

What does 'showing willingness' mean?

Front

could

Back

requesting in a polite manner

Front

might

Back

Expressing possibility with a hint of uncertainty

Front

ought to

Back

indicating duty or correctness

Front

should

Back

offering advice

Front

must

Back

expressing commitment

Front

shall

Back

making formal invitations/making suggestions

Front

would

Back

preference/polite request