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A pair of scissors is or are? which one? My teacher at lyceum said that it is are but I want to make sure.

8

"The scissors"

is plural.

However when you say "a pair of scissors", you are referring to one pair, hence it's singular.

  • Note that there's an exception to this rule for certain usages of number. E.g.: "A number of people are gathering outside the Capitol today." We also use the plural form for a few and a lot [of]. – Era Mar 3 '16 at 22:06
1

A 'pair' is two of something, but a pair can be singular or plural—it’s one of those odd English nouns (like couple) that can be singular or plural depending on how you’re thinking of the people or items in question.

The noun 'pair' can be followed by a singular or plural verb. The singular is always used when pair denotes the set taken as a single entity: This pair of shoes is on sale. A plural verb is used when the members are considered as individuals: The pair are working more harmoniously now. After a number other than one, pair itself can be either singular or plural, but the plural is now more common: I bought six pairs (or pair) of shoes. (Source)

Since 'pair' is a single entity and is a collective noun, you should use 'is', for your context.

Read more on the same question posted on a different community here, which has an accepted answer from FumbleFingers.