This advertisement has a picture of sad young woman holding a baby with a simile which reads, “It is like being grounded for 18 years”. The purpose of this simile is to persuade. Persuasion is to get someone to be something and / or to think something. This simile example wants young women to be carful and baby - having a baby is not fun. It persuades by comparing having a think with being grounded (not going out or partying) for 18 years, which is not fun for a long time.