Modale verbs

Examples

 Function

 Past form

Present form 

 we can attendd the show if you have time

 possibility

 could / might

 can - may

 Will you lend me the last comic show of gad Elmaleh ??

 requesting assistance

 would

 will

 I'd rather watch tom and jeery than Mickey mouse

 showing preference

 -

 would rather

 Students have to respect school rules

 obligation/certainly

 had to

 have to ; must

 You aught to revise your lessons before a test

 Advisability

 -

 ought to / should

 Students needn't take their books during exam day

 Lack of necessity

 -

 needn't

 They musn't cheat in the exam

 Lack of necessity and prohibition

 didn't have to

 don't have to - musn't

 The actor's face is reddish. He must have left embrassd

 certainly

 must have + past participle

 must

Mr. bean isn't plaing today

He could/might be tired 

 possibility/probability

 can/could+p.participle

may/might+p.participle

 can / may