By the end of this lesson, you will know:

• what modal verbs are
• how to use modal verbs to express obligation and freedom to act
• how to use modal verbs to express certainty and deduction
• how to use modal verbs to express ability
• how to use modal verbs in their past, present and future forms
• which some modal verbs cannot be used in the past or the future
• that some modal verbs can express a number of different concepts