What's the difference between "Beware" and "Be careful"?
Solution 1:
While the denotation of the two terms is very similar, the connotation is often quite different.
Beware is always a serious warning about something very dangerous.
Beware the Ides of March (there are guys out there with knives, and your name is engraved upon all of them)!
Be careful is a much more general advisory about exercising caution ranging from the ordinary to the extreme:
Be careful. Some of the paint may still be wet.
Be careful. The extraterrestrial flesh-eaters have landed and are looking for lunch!