Los verbos modales: must, have to, should, should have.

The soldier did a 180 and ran to tell the sergeant what the colonel said.; I saw the car crash and I was so shocked I did a double-take before I called 911.; That Lou did a job on me by telling the boss I wasn't willing to work on Saturday!; I'm going camping with you! My parents did an about-turn over letting me go!; Come on, Tim, be a good boy and do as I say.