Modal Verbs: CAN CAN Janet can run five km without stopping COULD Janet could swim in icy water WILL BE ABLE TO Janet will be able to operate a helicopter
Modal Verbs: MUST MUST Students must attend all their lessons HAD TO The grandparents had to attend all their lessons when they were at school WILL HAVE TO Your grandchildren will have to attend their lessons when they are at school
When you ask for permission … CAN Less polite COULDMAY Most polite
When you ask for help … CAN COULD
When you give a piece of advice SHOULD OUGHT TO
Remember these meanings It`s not necessary to do it NEEDN`T It will be better if you don`t do it SHOULDN`T It`s not allowed; it`s prohibited to do it MUSTN`T