pair

上句中的“are”应改为“is”。因为作“一副”“一双”“一对”“一条”解的“a pair of 与复数名词连用时，同一个从句中的动词要用单数”。请看下面的实例：

1. A pair of glasses costs quite a lot these days. 现时一副眼镜值很多钱。

2. A new pair of shoes brings more happiness to a child than a new car brings to a grown-up.

一双新鞋给儿童带来的快乐甚于一辆新车给成年人带来的快乐。

但是，a pair of 之后的代词以及定语从句中的谓语动词则常用复数形式：

1. I like this pair. How much $\$left\{\begin{array}{l} are they? \\ is it? \end{array}\right. 我喜欢这一双。(它们)卖多少钱?

2. She went to the wardrobe, chose a pair of shoes, put them on and leaned back in the chair. 她向衣橱走去，选了一双鞋，穿在脚上，然后依在椅背上。

3. He wore a pair of earphones, which were plugged into a tape-recorder. 他戴着一副耳机，耳机连在录音机上。

应当注意,当 a pair(of) 作“两个人”“一对夫妇”解时,其谓语动词通常用复数,但有时也可用单数:

1. A pair of teenage boys were smoking cigarettes... 两个十几岁的男孩正在吸烟……

2. The happy pair is/are going to Spain after their wedding. 这对愉快的新婚夫妇在婚礼后将去西班牙。