用于连接两个表示并列关系的名词或代词。如：
Both New York and London have traffic problems. 纽约和伦敦都存在交通问题。
The secretary both speaks and writes Spanish. 这位秘书不但能讲而且能写西班牙语。
You’ve given both your uncle and myself a lot of trouble. 你给了你姑父和我很多麻烦。
Sophia was both对ad and sorry to see her. 索菲娅看到她既高兴又难过。
The food was both bad and insufficient. 食物既坏又不够吃。
She was ashamed, both for herself and for Diana. 她感到羞愧，既为自己也为戴安娜。
I did all this both for you and for myself. 我做这一切是为了你，也为我自己。
He both speaks and writes Spanish. 他既会说也会写西班牙语。
Tonight they will both sing and dance. 今晚他们将又唱歌又跳舞。
说明：作为关联并列连词，它通常应连接两个相同性质的句子成分，但有时后一成分可能省略与前一成分相同的词。另外，若连接两个成分作主语，谓语总是用复数。如：
Both she and I are good at English. 她和我都擅长英语(from
www.zkenglish.com)。
Both teaching and research work are making great strides. 教学与科研都在大踏步前进。
Both she and Sophia were pleased with the girl. 她和索菲娅都喜欢这个姑娘。
We have black hair both。
We are very extroverted both。