The slogan is too mild.

Propaganda slogans have the effect of being widely publicized, and they will have different contextual effects because of their different places and objects.

1, no spitting! Add an exclamation point to emphasize the tone, which means warning, warning and prohibition. This means that it is non-negotiable and strictly enforced.

2, a small bite, thousands of bacteria. This is an explanatory propaganda language, which informs the "informed" of the harm of phlegm and makes the "informed" realize its harm and consciously follow and implement it. It is a gentle reminder without strong emotions.

The first sentence uses imperative sentences, with strong tone, commanding tone, firm and serious.

The second declarative sentence is warm, vivid and lively.