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Would there be a comma in the sentence after 'therefore'?

'These pipelines run for long distances and therefore(,) are susceptible to both natural and man-made phenomena. '

marked as duplicate by JMP, Edwin Ashworth, Jason Bassford, tchrist Jul 4 '18 at 12:42

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    You'd either use no comma at all (i.e., "...and therefore are...") or also put a comma before therefore (i.e., "...and, therefore, are..."). You wouldn't ever just use one comma. Since "therefore" is an adverb appearing directly adjacent to the verb, commas on either side aren't necessary but nonetheless are fairly common. Less common is putting them on either side when it appears after the verb it modifies (i.e., "...and are therefore susceptible...). – Billy Jul 2 '18 at 9:36

No. Not unless there is one after and -- in that case therefore would be parenthetical.

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