Can for ability and permission

Use can plus the base form of a verb for present ability: I can swim. She can drive. Can does not change with the subject, and the following verb never takes to or a third-person -s ending.

Make negatives with cannot or can't: He can't come. Make questions by putting can before the subject: Can you help? Short answers are Yes, I can and No, I can't.

Can also asks for or gives permission: Can I open the window? You can leave early. In more polite requests, could often sounds softer: Could you repeat that?