Question

Which of the following sentences has an error in agreement?

Everyone should wear his or her seatbelt while flying.

Flies is buzzing over the trash can.

Two girls and a boy are here to help deliver the papers.

Did Anne or her friend Mary leave her wallet on the table?

Answer 1

"flies is buzzing over the trash can." "flies" is a plural noun, and "is" should be "are."

if you're ever struggling with stuff like this, i find it easiest to try both the plural and singular form of the noun/verb, maybe say them out loud, and see what sounds right.