"Sell nothing to them!"
Translation:chaHvaD pagh yIngev!
It's not clear if you can add the pronoun after the verb to clarify whether you are speaking to one person or more than one person. I think it makes logical sense to me, but it doesn't sound right. Since we know it's fine without the pronoun and we can't be sure that it is acceptable with the pronoun, we do not allow the subject pronoun with imperatives in this course.