Computer Science Department, University of Colorado at Boulder, Boulder, CO, USA. steven.bethard@colorado.edu|Computer Science Department, University of Colorado at Boulder, Boulder, CO, USA. steven.bethard@colorado.edu|Computer Science Department, University of Colorado at Boulder, Boulder, CO, USA. steven.bethard@colorado.edu|Computer Science Department, University of Colorado at Boulder, Boulder, CO, USA. steven.bethard@colorado.edu