Answer:
In the sentence, "Mr. Wilkinson is trying to concentrate on his yard work but a swarm of bees keep distracting him." the incorrect verb used is "keep." This is because the noun, "swarm of bees" is collective. When collective noun is used, the verb should be in singular form. So the correct sentence should be "Mr. Wilkinson is trying to concentrate on his yard work but a swarm of bees keeps distracting him."
Step-by-step explanation:
A subject/verb agreement error occurs when the subject and verb of a sentence do not. agree in number. Singular Subject + Singular Verb = Agreement. Plural Subject + Plural Verb = Agreement.