GMAT Sentence Correction (SC) | Re: As algae spread in freshwater ponds and lakes, water quality

Dear gauravsoni,

The subject of "plays" is the gerund "reducing", which is singular.

Read the sentence like this:
Reducing (the nutrients (,such as phosphorus,) that enter a body of water) plays a major role in blah-blah.

The portion between "reducing" and "plays" just serves to identify the object of "reducing."

For example, see:
Singing the songs of Elvis is always a lot of fun.

What is fun? Singing, not the songs.


--Prasad
GMAT and MBA
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