Grammatical name for "one file contains"/"two files contain"

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Subject: Grammatical name for "one file contains"/"two files contain"
Posted by:  Swifty (steve.j.swi…@gmail.com)
Date: Wed, 06 May 2015

What is the grammatical name for the change in the verb between:

"One file contains …" and "Two files contain …"

I'm a programmer, and I'm writing a routine to help me output
grammatically correct messages.  I'm counting files that contain a
certain word (or set of words), so I need a routine to differentiate
between "One … contains" and "Two … contain" (of course, the number
might be anything greater than one)

I'd like my routine to have a name that matches the grammatical name for
the change in the verb.

--
Steve Swift
http://www.swiftys.org.uk/

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