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.

The thud of his head connecting with the glass caused a satisfying crunching sound.
Singular

" Snare drums, report to the band room before school tomorrow.
Plural

The pulse grew faster and the hum pitched even higher as the hydrogen was injected into the portion of the accelerator visible in the laboratory.

Singular