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: Strangely, their full garb that was perfectly natural in 1831 also seemed natural for standing in the middle of Schuylkill River Park.

SOLUTION: Singular

PROBLEM: How soon would the vodka wear off ?

SOLUTION: Singular

PROBLEM: One notebook had to be folded to fit.

SOLUTION:
Singular