GMAT Sentence Correction (SC) | GMATPREP ChallengeQ -The first detailed study of magpie attacks in Aus

E has one more thing to learn from..

Quoting Ron the Great:

a modifier must be either blocked off by commas or not blocked off by commas. you can't block off a modifier with a comma on one side but not on the other.

you can't do this. if a modifier is in the middle of a sentence, then you must either
* set it off with TWO commas, one on each side; or
* not set it off with commas at all.

the man who showed up yesterday is back again --> ok (meaning = there is more than one man, and i have
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