Indicating obligation and willingness

Students' problems

page 5 of 11

The modal could

Some students use could to say that someone has permission to do something in the future:

When you pass your driving test, you could drive.

This usage is not possible, instead it is necessary to use either can or will be able to:

When you pass your driving test, you will be able to drive.

For further information about the use of modal verbs related to permission, see
Indicating obligation and willingness: Using modal verbs to indicate obligation.

Introduction
Using modals with other verbs
The contracted form of will
Distinguishing between would and will
The modal could
The semi-modal need
The semi-modal dare
Adjectives used to indicate obligation
Distinguishing between nouns and other parts of speech
Distinguishing between suggest and advise
Distinguishing between willing and want