Is the distinction between "complex sentences" and "compound sentences" real? Is the distinction purely a matter of personal taste?

Question

I am not cheating on my homework.
In fact, I no longer have homework; I graduated from college years ago.
If you read the entire discussion below, and not just the begining, that should become apparent.

There is an example sentence I hope you might classify as "compound" or "complex."

Also, if the sentence is complex, then we must also identify the "dependent clause".

She did not cheat on the test, for cheating on the test would be the wrong thing to do.

If there is a dependent clause, then I have read that there is only one correct choice of dependent clause. The dependent clause is unique in complex sentences only having two clauses.

DEFINITIONS

In the following discussion a "punctuation mark" is defined to be something like a colon, a comma, a en-dash, etc...

DEFINITION OF BINARY SENTENCE

Suppose that a binary sentence is any sentence S such that at exactly one of the following statements about S is true:

• S contains no conjunctions, and the middle of S contains contains exactly one punctuation mark (colon, comma, en-dash, etc...)
• S contains exactly one conjunction, and all punctuation marks in S are at the very beginning or very end of sentence S.
• S contains exactly one conjunction, and S contains exactly one punctuation mark M not at the beginning or end of S. If you ignore space characters, then the conjunction and punctuation mark M are adjacent to each-other.

EXAMPLES OF BINARY SENTENCES:

• Cats are good pets, for they are clean and are not noisy.

• We have never been to Asia, nor have we visited Africa.

• He didn't want to go to the dentist, yet he went anyway.

MORE STUFF

I understand the following:

• An independent clause looks like a full-sentence or whole-sentence.
• A dependent clause is not a full-sentence. A dependent clause looks like a partial-sentence.

However, I do not understand:

• How to tell whether a binary sentence is complex or compound.
• If a sentence is binary and complex, I do not understand how we can determine what the one-and-only dependent clause is.

There are three possible ways to classify the example sentence. I am not sure which is correct.

ANSWER 1 OF 3

She did not cheat on the test, for cheating on the test would be the wrong thing to do.

• Classify for as a "coordinating conjunction."
• Classify the sentence as a non-complex "compound sentence."
• Sentence takes the form "[P], for [Q]" such that:
  • P = "She did not cheat on the test"
  • Q = "cheating on the test would be the wrong thing to do."

Note that both P and Q are independent clauses, because P and Q are full-sentences on their own. P and Q would not be incomplete/partial sentences on their own.

ANSWER 2 OF 3

She did not cheat on the test, for cheating on the test would be the wrong thing to do.

• Classify for as a "subordinating conjunction."
• Classify the sentence as a complex sentence (also, the sentence is not compound)

• The sentence takes the form "[P], [Q]" such that:

  • P = "She did not cheat on the test"

  • Q = "for cheating on the test would be the wrong thing to do."

    • Note that P is an independent clause.
    • P is a full-sentence (or almost a full-sentence). If you appended a period to the end of P it would stand on its own very well.
    • Q is an incomplete/partial sentence.

ANSWER 3 OF 3

She did not cheat on the test, for cheating on the test would be the wrong thing to do.

• Classify for as a "subordinating conjunction."
• Classify the sentence as a complex sentence (also, the sentence is not compound)

• The sentence takes the form "[P], [Q]" such that:

  • P = "She did not cheat on the test, for"

  • Q = "cheating on the test would be the wrong thing to do."

    • P is an incomplete/partial sentence. One is left asking "for what? She did not cheat on the test for what exactly?"
    • Q is an independent clause.
    • Q is a full-sentence (or almost a full-sentence). If you appended a period to the end of Q, then Q would stand on it's own very well.

FINAL NOTE

I was recently turned down for a tutoring job because I classified sentences as "complex" or "compound" differently than the test-writer did. If you think that the distinction between "complex" or "compound" is clear more than 90% of the time, then tell me what the rules are.

As best as I can tell, a binary sentence is "compound" if and only if the conjunction is one of the following words:

• "for"
• "and"
• "nor"
• "but"
• "or"
• "yet"
• "so"

The words in the list above are the set of all "coordinating conjunctions"
All other conjunctions are "subordinating conjunctions"
Is there some rhyme or reason for why some conjunctions are in one set, but not the other?

In "compound" binary sentences, the conjunction is not in either clause.
That is, for compound sentences, the conjunction is viewed as separate from the clauses. This is what makes the clauses full English sentence in their own right.

In "complex" binary sentences, the conjunction must be included inside one of the clauses. This is what makes one the clauses into a "dependent clause." If you remove the conjunction from the dependent clause, the dependent clause would be an independent clause.

• [She did not cheat on the test], [for cheating on the test would be the wrong thing to do.]
• [She did not cheat on the test, for] [cheating on the test would be the wrong thing to do.]

It seems to me that English grammarians always put the conjunction inside of the right-most clause. If they chose to put the conjunction inside of the left-most clause, then it would completely change whether the left-clause was dependent or independent.

I always have done badly in school unless one of the following occurred:
1. I could figure out on my own why something was the way it is
2. someone could tell me why it was that way.

I am unable to figure this one out on my own.

Can you tell me why there is a distinction between "complex" and "compound"? Is there some rule for determining which is which with at least 90% efficacy, or is it completely contrived?

Answer 1

Coordinating conjunctions are not limited to joining clauses. At least, most of them aren't. Examples like "not rain nor sleet", "strange but true", "fact or fiction", "odd yet endearing" and "tested and approved" help to show that these conjunctions create coordination of like constituents. Those like constituents can be, but need not be, independent clauses.

"For" and "so" are included in many lists of coordinating conjunctions. I suspect that those lists are simply wrong. Of course, if you're trying to land a tutoring position, you might be stuck with using the wrong list for the sake of your students passing set tests.

Your stipulations for a "binary sentence" have nothing to do with clauses and their relationships. For what it's worth, this sentence is complex. For the sake of another example, this sentence is neither complex nor compound. If you try to identify those through patterns of commas and conjunctions alone, you will fail.

Your answer 1 of 3 is reasonable, if we assume FANBOYS is a good list.

Your answer 2 of 3 is reasonable, if we assume that "for" is a function word that takes an argument.

Your answer 3 of 3 is something else. It claims something that just doesn't make sense.

She did not cheat on the test, for

That looks nothing like a dependent clause. That looks like an independent clause, followed by a preposition in desperate need of an argument. That poor, stranded "for" is all alone, without any kind of object or complement in sight.

Perhaps dependent clauses seem incomplete. For many people, that's a reasonable description that works rather well. That does not, however, work in reverse. Not everything that seems incomplete is a dependent clause.