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The pair (baby lion cubs) was / were born in July.

Should the verb be singular or plural in this sentence?
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Use the singular for "pair."

The pair was born in July.

The cubs were born in July.
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American is strictly "pair is/was"
I cannot speak for BrE, but that is untrue. I am liable to use either number.
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Comments  
There is a difference in American and British usage. American is strictly "pair is/was", British English will often have "pair are/were". The same goes for words like team and couple.
 Mister Micawber's reply was promoted to an answer.
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