Be careful when crossing the road.

Meaning: This is a warning to someone to pay attention and be cautious while crossing a street to avoid accidents.

Choice of Words: The verb be is used to express existence or a state of being. Careful means to take precautions to avoid danger or harm. Road is a paved way for vehicles to travel on. So, Be careful when crossing the road means to take precautions while walking across a street.

Alternative Expressions

Related Expressions