Numeral + 对 + Noun
The measure word 对 (duì) is used to count things that come in pairs or couples. It is commonly used for pairs of animals, people in a relationship, or matched objects. It emphasizes that the two items belong together as a unit.
公园里有一对老夫妻在散步。
Gōngyuán lǐ yǒu yí duì lǎo fūqī zài sànbù.
There is an elderly couple taking a walk in the park.
她买了一对耳环送给妈妈。
Tā mǎi le yí duì ěrhuán sòng gěi māma.
She bought a pair of earrings as a gift for her mother.
笼子里住着一对鹦鹉。
Lóngzi lǐ zhù zhe yí duì yīngwǔ.
A pair of parrots lives in the cage.