TASK DEFINITION: Given a sentence, generate a most likely context or previous statement. The previous statement should be relevant to the given statement.
PROBLEM: Someone collapses to his knees, then falls face down on the floor.

SOLUTION: Someone yanks out a handful of green goo.

PROBLEM: Leaving someone's room, someone stops as he hears the voice again.

SOLUTION: Professor and student look around nervously.

PROBLEM: They share a knowing look, then nod.

SOLUTION:
Someone adds hers, and someone tops it.