The document provides a comprehensive guide to the modal verbs 'can' and 'could', detailing their definitions, uses, and comparisons. 'Can' expresses ability, permission, and possibility, while 'could' indicates past ability, polite requests, and less certain possibilities. It also highlights common mistakes and stresses the importance of context in selecting the appropriate modal verb.

1. Understanding Modal Verbs: Can
and Could
A Comprehensive Guide

2. Introduction to Modal Verbs
• - Modal verbs are auxiliary verbs that express
necessity, possibility, permission, or ability.
• - Common modal verbs include can, could,
may, might, shall, should, will, and would.
• - Today, we will focus on 'can' and 'could.'

3. Definition of 'Can'
• - 'Can' is used to express ability or possibility.
• - It is also used to ask for and give permission.
• - Example sentences:
• - I can swim.
• - Can you help me with this?

4. Uses of 'Can'
• 1. Ability:
• - She can speak three languages.
• 2. Permission:
• - Can I go to the party?
• 3. Possibility:
• - It can rain tomorrow.

5. Definition of 'Could'
• - 'Could' is the past tense of 'can.'
• - It is used to express past ability, possibility, or
polite requests.
• - Example sentences:
• - When I was a child, I could climb trees.
• - Could you pass the salt, please?

6. Uses of 'Could'
• 1. Past Ability:
• - She could run very fast when she was
young.
• 2. Possibility:
• - If we leave now, we could catch the train.
• 3. Polite Requests:
• - Could you lend me your pen?

7. Comparing 'Can' and 'Could'
• - Ability:
• - Can: Present or general ability (I can drive.)
• - Could: Past ability (I could swim when I was
five.)
• - Possibility:
• - Can: Present or future possibility (It can rain
tomorrow.)
• - Could: Less certain possibility (It could rain
tomorrow.)

8. Examples and Practice
• - Fill in the blanks with 'can' or 'could':
• 1. When I was young, I ___ run very fast.
• 2. ___ you help me with my homework?
• 3. We ___ go to the beach tomorrow if it’s
sunny.
• 4. ___ I borrow your car tonight?

9. Common Mistakes
• - Confusing 'can' and 'could' in terms of time
reference.
• - Using 'can' instead of 'could' for polite
requests.
• - Example corrections:
• - Incorrect: Can you tell me the time, please?
• - Correct: Could you tell me the time, please?

10. Conclusion
• - Recap of the uses of 'can' and 'could.'
• - Importance of context in choosing the
correct modal verb.
• - Encouragement to practice using both modal
verbs in different scenarios.

11. Questions?
• - Open floor for questions and further
clarifications.