Can I take a photo?
Can I eat this sandwich?
Can I pay in Euros?
Can I swim here?
Can I use my mobile phone?
No, you can´t. It´s dangerous. Please stay on the beach.
Yes you can. Or you can use a credit card.
Yes, you can. but please talk quietly.
No, you can´t. No photos allowed.
Yes, of course. you can. It´s for you.