[youtube]http://www.youtube.com/watch?v=Icna9vsAh7Q[/youtube]

If you want to know how to use modal verbs, read this page and do the following exercises:

Modal verbs explanation in Spanish.

Modal verbs exercises. They are divided into these groups:

• certain, probable or possible
• ability, permission, requests and advice
• modals + have
• can, could and could have
• may, might, may have and might have
• can or could
• will or would
• will have or would have

Click on Modal verbs exercises and choose the exercise you want.