Today I would like to tell about very common mistake among learners of the Russian language. It is the way to say:

One cannot / It is not allowed/ It is forbidden.

To say this, we use the word нельзя́

We do not say “не можно”.

For example:

Здесь нельзя́ кури́ть. It is forbidden / not allowed to smoke here.

Or:

Нельзя́ вы́учить рýсский язы́к за ме́сяц. One cannot learn Russian for a month.

That’s it for today. I hope this small note was useful for you. Thanks for reading and good luck with your learning!