I was puzzled by the use of "puis" rather than "peux" in this example. I found this on Wiktionary.org: Puis (/pɥi/) is an archaic form of the first person present indicative peux. It is still used in inversion or with the conjunction si:<pre>
Puis-je vous aider? ― May I help you? Si je puis me permettre… ― If you don't mind…</pre>
There is a distinction in English between can and may although, you are right , it is not widely maintained nowadays. Technically, "can" implies ability to do something and "may" implies permission.
"Stop, Smith minor! I'm sure you can hit Jones major at 20 yards with your catapult - but you may not. Please get on with your work".