关于"a pair of"在主语及指代词数选择的用法规则解析

当"a pair of + 名词复数"结构用来描述一对或一双物体作为主语时，谓语动词通常采用单数形式。例如：

- "A pair of glasses costs quite a lot these days." (现在一副眼镜很贵)

- "This pair of jeans was too small for him." (这条牛仔裤对他来说太小了)

然而，并非所有情况都遵循这一规则，比如：

- "On the mantelpiece are a pair of bronze Ming vases." (壁炉台上有一对明代青铜花瓶)

- "This pair of shoes are shapeable." (这双鞋的样式可塑性强)

若"a pair of ..., pairs of ..."结构中的"pair"数量明确，则主语动词应与其一致。同时，指代这些"pair"的代词以及定语从句中的谓语动词一般采用复数形式，例如：

- "These pairs of socks are too small, so I can't wear them." (这些袜子太小，我不能穿)

- "This pair of shoes was expensive, but I like them." (虽然这双鞋贵，但我喜欢)

当"a pair of + 人物名词复数"结构出现时，其谓语动词通常用复数形式，尽管有时也可用单数表达：

- "A pair of teenage boys were smoking cigarettes." (两位十几岁的男孩正在抽烟)

- "The happy pair are/were going to Spain after their wedding." (这对快乐的新人将在婚礼后前往西班牙旅行)

- "She befriended a pair of openly gay nurses." (她与一对公开出柜的护士成了朋友)

而在某些情况下，如果将"a pair"视为一个整体，则动词可用单数形式：

- "We need an extra pair of hands if we're to finish on schedule." (如果我们想按时完成任务，就需要多一个人帮忙)