Grammar gems from the oddball category:
1. Compound possession…
Mike’s and Pam’s phones were stolen. (Each owned a phone; both were stolen.)
Mike and Pam’s phones were stolen. (The phones they owned together were stolen.)
But if one of the two owners is expressed as a possessive pronoun, we do this:
Mike’s and my house was robbed last night.
Otherwise, you’d have this:
Mike and my house were robbed last night. (Poor Mike. I hope he’s ok.)
2. Compound subjects of differing number…
Subjects and verbs should agree in number. But what do you do when the two subjects in an EITHER/OR construction are of different numbers? As in…
The players or the coach are/is at fault for the loss. (Only one of the two is/are at a loss.)
There’s no English verb form that accounts for a combination of singular and plural, so we let whichever is closer to the verb determine number. In this case, it’s coach, so we go with the singular verb is. It’s a compromise rule.
3. Offsetting parentheticals…
Sometimes the context determines the method of offsetting a parenthetical expression. Sometimes it’s a matter of preference…
a. commas (if the parenthetical is not too abrupt or digressive): The bowling ball, a gift from my sister, fell onto my foot.
b. parentheses (for added information): The bowling ball (a gift from my sister) fell onto my foot.
c. dashes (to emphasize a break in the flow): The bowling ball—a gift from my sister—fell onto my foot.
4. The pronoun EACH…
There’s nothing weird about the word each, but we screw up so often in how we use it you’d think there was some weird exception to the agreement rules. There’s not. Each is singular. Always. So it should always take a singular verb or be the antecedent to a singular pronoun.
The following are correct:
Each of the girls brought her books to school. (not their books)
Each of the umbrellas closes with the push of a button.
If neither sounds weird to you, then your grammar is standard-issue. Congratulations.