Not only … but also … 與 “both … and …”、”neither … nor …”、”either … or …” 等一樣，在英文中叫做相關字組 (correlatives) 或相關連接詞 (correlative conjunctions)。它們的用法特色是，與其兩個元素連用的詞類和結構必須平行對稱、對仗工整。
Not only … but also … (不僅…而且…；不但…而且…) 係用在正式的上下文中。例如：
- The war caused not only destruction and death but also generations of hatred between the two countries. (戰爭不僅造成了破壞和死亡，也造成了兩個國家之間代代相傳的仇恨)
- The car not only is economical but also feels good to drive. (這部車不僅省油，而且駕駛感良好)
- This investigation is not only one that is continuing and worldwide but also one that we expect to continue for quite some time. (這項調查不僅是一項在全球範圍內持續進行的調查，而且也是一項我們預計將持續相當長一段時間的調查)
有時我們可以省略 but 或 also。例如：
- Not only did he turn up late, he also forgot his books. (他不但遲到，還忘了帶書)
- I identified with Bill Gates not only as an entrepreneur but as a philanthropist. (我認同比爾蓋茲不僅是一位企業家，而且還是一位慈善家)
為了加強語氣，我們可以將 not only 挪到句子的開頭。當我們這樣做時，我們要使用倒裝句，也就是把主詞和動詞對調。例如：
- Not only was it raining all day at the wedding but also the band was late. (婚禮上不僅下了一整天的雨，而且樂團還遲到了)
- Not only will they paint the outside of the house but also the inside. (他們不但粉刷房屋的外部，還粉刷房屋的內部)
若沒有助動詞或主動詞 BE，則使用 do, does, did。例如：
- Not only did Helen forget my birthday, but she also didn’t even apologize for forgetting it. (海倫不但忘了我的生日，甚至也沒有為此道歉)