The following is a sentence from an article I was reading:

But the problem is that, after the Trump Administration wasted the time that was available to prepare for the pandemic’s spread, by instituting widespread testing and creating additional hospital facilities, today’s Draconian measures are both necessary and probably insufficient.

(Source: In the Midst of the Coronavirus Crisis, We Must Start Envisioning the Future Now)

My question is why the author put a comma before “by”. Is it used here to avoid confusion because with a comma, it means that “instituting widespread testing and creating additional hospital facilities” are how the time was being wasted, but without a comma, they could be interpreted as the ways to “prepare for the pandemic’s spread”? Or is it used just to put a pause in the parenthetical element, because otherwise it would be too long?

Thanks for any help you can offer.

2 Answers 2


In my opinion the comma facilitates appreciably understanding; if there is no comma you may possibly follow the logical path of thinking that the pandemic spread is brought about by something, although the word "instituting" should clear that idea right away. Instead the comma makes it more likely that the prepositional phrase "by instituting … facilities" does not modify the noun phrase "pandemic's spread" but the verb "wasted"¹ and so a spurious indication is made less prominent. Your first supposition is the proper one: avoid confusion, make the meaning as clear as possible.

I say above "more likely" and that the spurious clue is made less prominent because it is possible to have a modification of the noun phrase and still have the prepositional phrase set out between commas. This is according to the principle of restrictive and descriptive elements in a sentence, a typical case being that concerning relative clauses; it is also applied for prepositional phrases (ref.) and thus, in this example it is finally the context that helps determine what element in the sentence is being modified.

¹ It is not very logical to think that "wasted" is the verb being modified, as user PKY noticed in the comments. The verb being modified is almost without doubt the verb "prepare".

  • If there is no comma, is it possible that the prepositional phrase "by instituting ... facilities" can be seen as modifying "prepare for", because "prepare for something by doing something else" also makes sense? @LPH
    – PKY
    Mar 31, 2020 at 11:44
  • You said that "it is possible to have a modification of the noun phrase and still have the prepositional phrase set out between commas," so I made up this sentence: The spread of the coronavirus, by droplets or physical contacts, is containable. Is this what you mean? And does it sound natural? @LPH
    – PKY
    Mar 31, 2020 at 12:08
  • @PKY 1/ In fact, what you suggest is far from deprived of a basis and it appears more logical to think as you do: "instituting widespread testing …" is how to prepare for the pandemic's spread. I'd say that this the likely interpretation whether there is a comma or not. 2/ This example shows the descriptive use of a prepositional phrase very well. I find it natural; however, certain writers will find the use of dashes more explicit: "The spread of the coronavirus — by droplets or physical contacts — is containable.".
    – LPH
    Mar 31, 2020 at 15:20

The writer is using the commas to bracket a dependent clause.

An American writer is likely to put commas at the start and end of the clause. A British writer is less likely to, since the sentence would mean the same thing with or without the commas. When they're not needed for clarity, the British often skip them.

So the choice is to use both or neither. It would be wrong keep one and leave out the other. That would be confusing.


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