Which is correct?
|Sometimes Perl or Python ____ used instead of PHP.
When two or more singular nouns or pronouns are connected by “or” or “nor”, use a singular verb. Think of it this way: We’re saying sometimes Perl (is used instead of PHP) or Python is used instead of PHP.
Go see the Purdue Owl for more about subject-verb agreement.
Thanks to Peggy Rouse (@whatisdotcom) for this one.