Difficulty: Moderately Easy
Step1
Make both pronoun and antecedent plural or singular. In the above sentence, both "Billy" and "he" are singular. Therefore, the sentence is correct. An example of plural agreement is: "When my parents work late, they eat dinner at the office."
Step2
Know how to handle indefinite pronouns. Some of these include: everybody, everyone, anyone, anything, either, neither and each. Infinite pronouns are always singular. Incorrect sentence: "Everyone needs to take their car for a yearly vehicle inspection." Correct sentence: "Everyone needs to take his car for a yearly vehicle inspection."
Step3
Rewrite sentences in plural if you are worried about using masculine pronouns. In the above sentence, many grammar experts would not use the masculine "his" to agree with the gender neutral "everyone." However, the use of his/her sounds awkward. One way to fix the above sentence is by making both antecedent and pronoun plural by replacing "everyone" with "people." Correct sentence: "People need to take their car for a yearly vehicle inspection."