Fixing an Ambiguous Sentence

Sometimes, when you read a sentence with two modifiers or two antecedents, you can find it confusing to decide which modifier goes with which part of the sentence. Then you have to pause and figure out the most logical meaning. Take a look at this sentence:

The vapor trails were observed dispersing from several ground stations.

https://apod.nasa.gov/apod/ap190408.html

Okay, we have two antecedents here. Were the trails “observed from several ground stations” or were they “dispersing from several ground stations”?

Lots of times you can solve the ambiguity by changing the order of part of the sentence.

• The vapor trails from several ground stations were observed dispersing.
• The vapor trails were observed from several ground stations dispersing.
• The vapor trails were dispersing observed from several ground stations.
• The dispersing vapor trails were observed from several ground stations.
• Several ground stations observed the dispersing vapor trails.
  

The first three are all pretty awkward; the fourth one is better, but it implies the existence of vapor trails that weren’t dispersing. The last one is best, and notice it doesn’t use the passive!

I’ve been cheating on you. Here’s the context:

The atmosphere over northern Norway appeared quite strange for about 30 minutes last Friday when colorful clouds, dots, and plumes suddenly appeared. The colors were actually created by the NASA-funded Auroral Zone Upwelling Rocket Experiment (AZURE) which dispersed gas tracers to probe winds in Earth’s upper atmosphere . AZURE’s tracers originated from two short-lived sounding rockets launched from the Andya Space Center in Norway. The harmless gases, trimethylaluminum and a barium / strontium mixture, were released into the ionosphere at altitudes of 115 and 250 km. The vapor trails were observed dispersing from several ground stations.

Since the context tells so much about the vapor trails, you don’t need to describe them again in the last sentence. Just add the new information; say this:

The vapor trails were observed from several ground stations.

Or

Several ground stations observed the vapor trails.

And here’s a picture:

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The rule:

• “Who” refers to people
• “That” doesn’t.

Here’s a good illustration of why this matters:

Is he referring to the ex-wife or to the phone message? Ambiguity is bad except in poetry and lies.

A writing tip: pronouns are supposed to refer to the closest possible antecedent. That’s why I avoid pronouns. Too easy to lose track of the antecedent.

These are possible alternative sentences:

• …message from an anonymous ex-wife who told me…
• An anonymous ex-wife sent me a message that told me…
• An anonymous ex-wife told me…

I suppose I could add that the doctor appears to be violating patient confidentiality.

First the example:

The Sapelo Island Lighthouse is the second-oldest brick lighthouse in the country dating back to 1820.

https://blog.thediscoverer.com/10-best-usa-islands-outside-hawaii/

Here’s a picture of the lighthouse:

Sometimes you use a phrase (no verb) or a clause (has a verb) to describe something. When you separate that description from what it describes with a comma, we call it non-restrictive. It’s an aside. No comma? Then it’s restrictive, part of the definition of what you’re describing.

That’s a little bit tricky to follow, so let’s look at that sentence about the lighthouse.

It’s the second-oldest brick lighthouse in the country. So far, so good. But what about “dating back to 1820”?

• Is it the second oldest one that dates back to 1820?
• Is it the second oldest one, and it happens to date back to 1820?

The first bullet is restrictive, part of the definition. Apparently we have lots of lighthouses that date back to then, and this is the second oldest. Seems unlikely.

The second bullet merely adds some information about the lighthouse; it dates back to 1820. It’s non-restrictive.

What a difference a day comma makes!

Remember: no comma, gotta have it—restrictive. Comma, extra info—non-restrictive.

The rule is that a pronoun is supposed to refer to the noun closest before it (the antecedent), so the cartoonist has a point.

The closest noun is “tires”…

I don’t happen to know the technical term for it, but when you refer to something in, say, the third person, don’t switch to using, say, the first person when you refer to it.

Perhaps best explained with an example:

Here’s the sentence:

China has changed that market dramatically, and their decision has forced the rest of the world to become more self-reliant and responsible in our waste management.

• China—third person; their—third person. They refer to the same entity, so okay.
• rest of the world—third person; our—first person!
• They refer to the same entity, so not good

The sentence could have used “us” instead of “rest of the world” and it would have been okay. The sentence could also have used “their” instead of “our” and that would have been okay, too, but I prefer using first person because the sentence already used the third person for China, so using the first person when you refer to someone else is a little smoother.

So what do you call it? Person agreement? Personal coordination? How about clear instead of confusing?