John McPhee is one of America's great writers, and apparently teachers, as one can gather from this piece in the Princeton Alumni mag by Joel Achenbach. To understand the following, "greening" is McPhee's word meaning the excision of words from a piece as needed to fit space, etc. but without damage to the author's content and style.
"He made us green a couple of lines from the famously lean Gettysburg Address, an assignment bordering on sadism."
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