For each {context, question, answer} triple, <cite>AddSent</cite> does the following: (1) Several antonym and named-entity based semantic altering perturbations (swapping) are applied to the question; (2) A fake answer is generated that matches the 'type' of the original answer (e.g., Prague → Chicago, etc.); (3) The fake answer and the altered question are combined into a distractor statement based on a set of manually defined rules; (4) Errors in grammar are fixed by crowd-workers; (5) The finalized distractor is appended to the end of the context.