Archetypal sentences in context

Susan builds upon her previous knowledge that one tú command ends in -s and the other doesn’t.  In order to remember whether the affirmative or the negative tú command ends in –s, she recalls a situation when she was in a park in Spain and she heard a father say no lo hagas ‘don’t do that’ to his son.  Susan knew he was using a negative tú command, so then she realized that the negative tú commands are the ones that end in -s. Susan also remembered that people often said ven aquí ‘come here’ to their dogs.  By recalling this sentence she remembers that affirmative tú commands don’t end in -s and Susan is able to remember the irregular form of the verb venir.