If someone or something is an advertisement for something, they show its good effects.

I'm afraid I'm not a very good advertisement for the diet since I've actually put on weight! 恐怕我不是这套减肥饮食计划的活广告，因为我的体重实际上是增加了！

She's a great advertisement for the benefits of exercise and healthy eating.

This referendum was not really a good advertisement for direct democracy.

Talented and charming, he could not have been a better advertisement for the school.

Wicks is a good advertisement for the restorative powers of a good rest.