Watch your step!
This idiom has two slightly different meanings. In the literal, or direct, sense, it
means to be careful when walking. People will often say "Watch your step"
when there are steps at an entrance or exit, for example, in entering a bus. Another
meaning is to be careful in another sense. If a son wants to ask his father for a favor,
the mother might say, "Watch your step! Your dad is very angry right now."