TASK DEFINITION: In this task you are given a sentence. You must judge whether subject of the main clause is singular or plural. Label the instances as "Singular" or "Plural" based on your judgment.
PROBLEM: Alexis headed back to her room.

SOLUTION: Plural

PROBLEM: Clearly, a notion she hadn't suspected.

SOLUTION: Singular

PROBLEM: Things had changed a little since the last time I'd gone shoe shopping.

SOLUTION:
Plural