1. Period (.) - This is the most common and neutral option, making it a simple statement.
"Never cross the street without looking both ways."
2. Exclamation point (!) - This option adds emphasis and urgency, making it a warning.
"Never cross the street without looking both ways!"
3. Question mark (?) - This is less common, but could be used if the statement is meant to be rhetorical or questioning.
"Never cross the street without looking both ways?"
4. Colon (:) - This could be used to introduce a list of reasons why one should look both ways.
"Never cross the street without looking both ways: it's the safest way to cross."
The best punctuation choice will depend on the specific context and the desired tone.