What is the actual "rule," and which one is correct?

Ports 10-20 have been or has been opened.

I strongly believe that "have been" is correct. I do not however remember the "rule," so I cannot explain why it is correct.

Can anyone give me some foundation to build my case, please?

closed as general reference by FumbleFingers, RegDwigнt Feb 24 '12 at 21:32

This question is too basic; it can be definitively and permanently answered by a single link to a standard internet reference source designed specifically to find that type of information. If this question can be reworded to fit the rules in the help center, please edit the question.


Plural subjects (ports) take plural verbs (have). I don’t understand the question.

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