GMAT Sentence Correction (SC) | Re: A March 2000 Census Bureau survey showed that Mexico

The underlined portion is an absolute phrase modifier. An absolute phrase modifier modifies an entire clause in some way and has the structurenoun / noun phrase + noun modifier .

Here,

Absolute phrase modifier: the largest share that any country has contributed since 1980. (noun = the largest share, noun modifier = that any country has contributed since 1980).

The
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