Why is NLP hard? Variability: He drew the house He made a sketch of the house He showed me his drawing of the house He portrayed the house in his paintings He drafted the house in his sketchbook Ambiguity: She drew a picture of herself ~ sketched, made a drawing of cart drawn by two horses... ~ pulled He drew crowds wherever he went ... ~ attracted The driver slowed as he drew even with me ~ proceeded The officer drew a gun and pointed it at ... ~ took out, produced