watch it

keep a close watch

to pay careful attention to a situation or a thing, so that you can deal with any changes or problems.

keep watch

To guard; to watch over someone or something.

on one's watch

During the period of time when one is in a position of authority or responsibility.

set one's watch back

To ponder or experience a past time.

set one's watch by someone

To know the current time by observing a very punctual and reliable person going about their regular routine.

watch one's language

To be careful about what one says, in particular the avoidance of foul language.

watch one's mouth

To be careful about what one says, especially with regard to disrespectful or profane language.

watch one's step

To be cautious.