by Sage Pearce-Higgins Thu Mar 21, 2019 7:30 am
Yes, I see now. It's pretty complicated! Ron's distinguishing between a verb participle and a noun. Both are -ing words formed from verbs. As I understand it, he's saying
The elephant population is dying out because of poaching. is fine, since the -ing word is a noun
but
Sulfur dioxide is an especially serious pollutant because of diminishing... in the above example is not okay, because the -ing word is a verb participle
and
Because of diminishing returns... is okay, since the -ing word is an adjective.
For me, this is not a useful rule. I mean, how can you be sure that an -ing word is a noun, an adjective, or a verb participle? I'm not surprised that you're confused! To be honest, I do pretty well on GMAT and have never considered this distinction. Plus, looking closer at Ron's posts, it seems that he contradicts himself.
I would encourage you to take a much less grammatical approach and focus on the meaning of the sentence. Many examples of 'because of -ing' are incorrect because it's not clear who is doing the action. Take my example above: 'She was tired because of playing football.' This doesn't make clear that she was playing football, and so the sentence 'She was tired because she had been playing football.' would be preferable.
Finally, remember that, in SC problems, you're faced with alternatives. Try to find some more examples of splits using 'because of' in GMAT problems and consider the meaning of the different alternatives.