Make subjects and verbs agree.

21Make subjects and verbs agree.

In the present tense, verbs agree with their subjects in number (singular or plural) and in person (first, second, third): I sing, you sing, she sings, we sing, they sing. Even if your ear recognizes the standard subject-verb combinations in 21a, you will no doubt encounter tricky situations such as those described in 21b–21k.