The document discusses modal verbs and the verbs "can" and "be able to". It provides definitions and examples of how these verbs are used to express ability, permission, requests, obligation, advice, possibility, and past habits. Key points include:
- Modal verbs do not use 's' for third person singular and make questions through inversion.
- "Can" and "could" express ability and possibility, while "must", "should" express obligation or advice.
- "Can", "could", and "may" express permission, and "will" and "would" discuss habits.
- "Can" is used for present ability while "be able to" can be used in all