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: Ahead he could see two Agents, one on either side of the doors.

SOLUTION: Plural

PROBLEM: All the bearded hunter could do was stare wide-eyed.

SOLUTION: Singular

PROBLEM: Every particle of her being was aching for this, had been aching for this since the week before.

SOLUTION:
Singular