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.

His footsteps echoed like a death knell when he walked away.
Plural

The courtyard is shaking so badly that for a second I'm not sure I haven't caused another earthquake.
Singular

The aliens were about to annihilate life on planet Earth.

Plural