4. 双 (shuāng)
“Pair” is a typical English measure word. In Mandarin, we also have a measure word for “pair”, which is 双 (shuāng). Check these examples: 一双鞋(yī shuāng xié)(a pair of shoes), 一双筷子(yī shuāng kuài zǐ)(a pair of chopsticks).
*Note: We don’t use 双 (shuāng) for a pair of pants; instead, we use 条 (tiáo). One reason is that pants are long, narrow and skinny. More importantly, a pair of pants are not two separated things. 双 (shuāng) are usually used for a pair of two separated things.