A pair of…

In the poem, Papa lost his only pair of spectacles. The word 'pair' means two things that go together. Your book, Santoor, starts with 'a pair of shoes': one shoe for each foot.

Many things come in twos. We wear a pair of socks and a pair of shoes on our feet. In winter we wear a pair of gloves to keep our hands warm. We wear a pair of earrings, one in each ear. For a game of badminton, two players need a pair of rackets.

Some things are ONE thing with two matching parts, and we still say 'a pair of'. Trousers have two legs, so we say a pair of trousers. Scissors have two blades, so we say a pair of scissors. Spectacles have two glasses, one for each eye, so we say a pair of spectacles.

So when you see two things that belong together, or one thing made of two matching parts, you can say 'a pair of'.