SEE refers to the visual impressions that come to our eyes. Seeing is not always deliberate, it may be accidental.           We saw a bat flying across the room

      LOOK suggests intention: we are trying to see something.     He looks at every girl he sees

      WATCH implies looking, but suggests that something is moving, changing or developing in front of us.

                       I watch a football match every Sunday

      Be careful!       We watch TV          but      We see a film or a play.