A simple lesson about the strength of the mighty little comma can be learned by noting the difference in meaning that results depending on its presence or absence at the end of a parenthetical phrase.
More specifically, in the types of sentences shown below, when an attributive phrase—one that identifies the source of the information provided in the framing sentence—is inserted in the midst of the sentence and a comma precedes the interjection but none follows it, what is said is often not equivalent to what is meant:
1. “Every nine years, it was decreed that the fragment must be conveyed to another place of sanctuary.”
The point of this sentence is that an action is described as having occurred every nine years, and that this action was decreed. That latter detail is the content of the attributive phrase. But without a comma closing the interjection, the implication is that the decree was issued every nine years.
However, what the sentence means is that a decree was issued requiring the action to occur every nine years—that’s a much different idea, and this slightly revised sentence correctly expresses it: “Every nine years, it was decreed, the fragment must be conveyed to another place of sanctuary.”
2. “By the end of the century, estimates are that one in three people will be living in poverty.”
This sentence is not as far afield from the intended meaning as the original sentence in the previous example, but it does suggest that such estimates will be released by the end of the century, rather than that current estimates predict the stated outcome.
This revision states the point more clearly: “By the end of the century, estimates are, one in three people will be living in poverty.”
3. “Instead of embracing our civil rights future, the commission’s report says the Bush administration has begun backsliding into the past.”
At first glance, this sentence seems to have the same not-quite-right structure of the second example, but it actually introduces a serious miscommunication. The suggestion is that the commission report, not the Bush administration, is failing to embrace our civil rights future, and that the commission is making the statement in place of that responsibility.
The mere insertion of a comma sets the sentence right (in this case, an optional that is not included, so no deletion of same is necessary): “Instead of embracing our civil rights future, the commission’s report says, the Bush administration has begun backsliding into the past.”
4. “Up to my junior year at the University of Michigan, I am forced to admit that I had always tried to get A’s.”
The writer, this sentence suggests, was forced to make an admission until reaching their third year of college, at which time the confession was no longer required (but in that case, am should be replaced by was).
But the admission is parenthetical to a different thought, which is that the writer strove for the highest letter grade for only their first two years in higher education: “Up to my junior year at the University of Michigan, I am forced to admit, I had always tried to get A’s.”
5. “As far back as his childhood, he told me he had wanted to be a scientist.”
As punctuated, this sentence tells the reader that the would-be scientist had shared his ambition with the writer since the other person had been a child. If this is what the writer means, the beginning of the second part of the sentence should include had (“he had told me”).
But if the writer is relating what the other person had shared more recently about his childhood goal, a comma should follow me to set off the attributive phrase “he told me”: “As far back as his childhood, he told me, he had wanted to be a scientist.”
This article originally ran on DailyWritingTips.com.