Possible long-term consequences of the “greenhouse effect,” the gradua

When it comes to most SC issues, we tend to get into trouble when we overcomplicate things or rely too much on terminology. For parallelism, it's easiest to think about what general role each element in the construction is playing. If the elements are playing the same general role and seem logical, assume that the parallelism is fine.

For example:

"On his vacation to Australia, Tim enjoyed swimming with sharks and running great distances."

When you're evaluating the parallelism here, it's enough to see that Tim enjoyed two activities, "swimming" and "running", and that both of those activities are expressed as nouns or noun phrases.

What you don't want to do is start obsessing over whether the prepositional phrase included in the first noun phrase, "with sharks," necessitates another prepositional in the second noun phrase. And you certainly wouldn't want to think, "okay, I've got 'preposition + sea creature' in my first element, so clearly I need 'preposition + sea creature' in my second." Otherwise, you run the risk of forcing Tim to run with whales.

Instead, simplify your approach and emphasize meaning over terminology. Accept that you've got two noun phrases, recognize that the construction is logical, and move on to other issues.

I hope that clears things up!