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: The email, as it was open and apparently unfinished, could have easily been a clue as to the whereabouts of General White and his family.

SOLUTION: Singular

PROBLEM: He hoped she'd stay, hoped they could explore the possibilities.

SOLUTION: Plural

PROBLEM: Your distances this year have been your best yet !

SOLUTION:
Plural