Sentence 1: Mary stopped at the store to buy something for the office picnic. 
 Sentence 3: The cole-slaw smelled a bit off, but Mary set it out on the table 
 Sentence 4:  Later that day, several people at the picnic felt ill 
 Sentence 5:  Mary said her co-worker's potato salad must have spoiled 
 Option 1: She bought soda. 
 Option 2: She saw a quart of coleslaw on sale and bought it.