P 双筒望远镜　a pair of glasses like short telescopes for both eyes, used for looking at distant objects

1. binoculars是复数形式的名词，但表达的是单数概念，若表示数量，须用单位词pair. 如“一副双筒望远镜”是a pair of binoculars.
2. binoculars用作主语时，谓语动词应该用复数形式。

　I watched the birds through my binoculars.　我用双筒望远镜观鸟。
　He watched the play through his binoculars.　他用双筒望远镜看戏。
　The binoculars are in that leather case.　双筒望远镜在那皮箱里。