We don’t know what we don’t know, and we can’t look up what we don’t know when we don’t know what to look up.

Whew. I think I got that sentence meaning what I intended it to mean.

There are plenty of grammar and punctuation rules that we’re not up on. Unless you’re a true expert, there’s going to be something you don’t know. And when you don’t know something, it’s impossible to look up information about it—if you don’t know what it’s called or what it does, how would you know how to search or even that a search was necessary?

So… This article is a list of the odd or unusual or perhaps unfamiliar rules of grammar and punctuation. I may have covered some of these in other articles, but I thought listing them in one place would be helpful.

I’m sure I’ll add to the list, and I welcome your suggestions.

Unfamiliar Grammar

1. Compound possession. Do the two entities in your subject share ownership of items or do they each own one of the item?

Bob’s and Kim’s cars are blue.

Bob and Kim’s cars are blue.

In the first case, Bob and Kim do not share ownership of their blue cars. They separately own one or more blue cars. (Or, they each own one or more blue cars and share ownership of another. If such is the case, consider rewriting the sentence to make clear the specifics.)

In the second example, they share ownership of at least two blue cars.

If the possession is shared by the compound subject, use an apostrophe with the second noun to show that shared possession.

If there is no joint ownership—or if they share ownership and independently own at least one of the objects—each noun must use the possessive form.

However…

If the compound subject is made up of a noun and a personal pronoun, both the noun and pronoun need to be made possessive.

Todd’s and my house exploded last night.

Otherwise, you’d have a construction such as

Todd and my house exploded last night.

This second sentence could be true, but it doesn’t have the same meaning as the first example, which says that the house that the speaker and Todd co-own exploded. The second example says that the house owned by the speaker exploded and that Todd exploded as well.

2. Alternative subjects and verb agreement. Subjects can share a verb but not be compound subjects. That is, if they’re not joined by and but are instead joined by or, nor, or but, they are alternative subjects.

Typically, a compound subject requires a plural verb.

Susie and her sisters want to go to the beach.

Her sisters want to go to the beach.

Susie and her sister want to go to the beach.

But, Susie wants to go to the beach.

There is an exception when the compound subject operates as a single subject.

Tea and crumpets is a dream meal for my mother.

The oddity—The verb for subjects connected with or, nor, and but is plural or singular depending on the subject closest to the verb.

Either the man or his sons want to sell the property.

Neither the sons nor the father wants to sell the property.

Not the envelope but the stamps taste awful.

Not the stamps but the envelope tastes awful.

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Unfamiliar Punctuation

1. Dialogue interrupted by thought or action or description—something other than a dialogue tag—requires specific punctuation, something more than commas.

“Drop your weapon, chump”—my assailant sounded like every B-movie bad guy from the ’40s—“and turn around.”

“The beauty of it”—I was really pouring it on—“is that it works.”

“Truth is”—she reached for a tissue—“I truly loved my husband.”

Enclose the dialogue in quotation marks, without using commas or extra spaces and enclose the interruption (no capital letter) in a pair of em dashes, without spaces between the dashes and the words closest to them. The final punctuation mark, of course, comes before the closing quotation mark.

2. Digressions, parenthetical statements, commas, and parentheses. Parentheses may be used to set off additional information or a digression in a sentence. The sentence interrupted by parentheses should be grammatically correct if the parenthetical element is removed. Thus…

Belinda stared at the ornate crucifix (the very one Dr. Smithson had sought for the length of his career) and started to cry.

Belinda stared at the ornate crucifix and started to cry.

If a comma is required for the sentence at the same place the parenthetical element is added, put the comma after the final parenthesis.

If a human wanted to own a gnome, he’d need a permit and inoculations.

If a human wanted to own a gnome (and who would want one of those horrid, messy creatures), he’d need a permit and inoculations.

Digressions can also be set off by commas or dashes, resulting in a different emphasis for the digression.

She owned the same funky shoes, only in black, and she’d worn them yesterday.

Tom—the Tom from Banberry’s and not the one from Houston’s Limited—was a rake of the lowest, not highest, order.

Note that a comma is unnecessary when the digression is set off by dashes, even if a comma is required in the sentence without the digression.

Jill, the detective’s daughter, challenged her father’s superiors with the information she’d discovered.

Jill, the detective’s daughter—and an experienced investigator in her own right—challenged her father’s superiors with the information she’d discovered.

2. Parentheses at the end of a sentence. If the parenthetical phrase (or sentence) comes at the end of a sentence, the terminal punctuation mark remains outside the parentheses.

Daisy’s kids wanted to go to the park (you remember how much they loved Turner’s Point Park).

Expectations of finding the victim were slim since he’d been missing for more than five days (and the killer’d never left anyone alive for more than two).

If the parenthetical is a full sentence or paragraph and not part of another sentence, of course the end punctuation mark is included within the parentheses.

It was true. (Yet, even if it hadn’t been, no one would have known.)

3. Dialogue abruptly cut off. An em dash is used to cut off dialogue (an ellipsis is used for dialogue that trails off). Only the closing quotation mark follows the dash—no comma, no space, no terminal punctuation marks.

“Rats! I’d always wanted t—“

4. Comma use for multiple adjectives. Use a comma to separate coordinate adjectives (they can be joined by and, or their order can be changed and the sentence still makes sense).

The rude, brilliant man was always unhappy.

The brilliant, rude man was always unhappy.

The rude and brilliant man was always unhappy.

Do not use a comma to separate cumulative adjectives, adjectives that must be used in a specific order for the sentence to make sense.

The long red truck veered into my lane.

The red long truck veered into my lane. X

Do not use a comma when the adjective modifies both the noun and the other adjectives modifying it. (Attached in this example modifies the tattered and battered map.)

The attached tattered and battered map didn’t lead to treasure.

The attached, tattered and battered map didn’t lead to treasure. X

Comma use with descriptive adjectives can also be determined by the class of adjective. The common classes are General, Age, Size, Color, Shape, Material, and Origin. If multiple adjectives are from the same class, separate them with commas. If they’re from separate classes, do not use a comma.

The scarred old man was really a softie. (General & Age)

I plucked the fuzzy green dice from the dashboard. (General & Color)

The elegant, fastidious woman brushed off the crumbs and sneered. (General & General)

The hopeless, broken man fell into the stinky, polluted gutter. (General & General; General & General)

Rover Jr. chased the bouncing red plastic ball right out the door. (General, Color, & Material)

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A writer’s misuse or lack of knowledge about these rules is not likely to keep an agent or publisher from wanting his manuscript, but knowing them, and using them, will help that writer produce a cleaner manuscript.

http://theeditorsblog.net/2011/02/14/rules-of-grammar-punctuation-the-weird-odd-or-unfamiliar/