TASK DEFINITION: In this task your given two statements. You must judge whether the second sentence is the cause or effect of the first one. Label the instances as "cause" or "effect" based on your judgment. The sentences are separated by a newline character.
PROBLEM: The boy's back ached.
His backpack was heavy.

SOLUTION: cause

PROBLEM: I excused myself from the group.
My phone rang.

SOLUTION: cause

PROBLEM: The girl shared her lunch with her friend.
Her friend forgot to bring his lunch.

SOLUTION:
cause