not only ... but also

轉載自http://210.240.55.2/~t311/moe/engb6/b6grammar/b6notonly.htm

not only ... but also ... 是「不僅‧‧‧也是‧‧‧」的意思，其實它和 and 的意思相同，只不過在用法上略有些差別而已。先看看底下簡單的例子：

e.g.　　1. She is not only nice but also beautiful.

　　　　2. Ted plays not only baseball but also soccer.

　　　　3. Sarah gave her sister not only a pen but also a dictionary.

　　　　4. We enjoy not only the movie but also the time with our friends at a movie theater.

你是否發現到，若把上述的三個句子改為用 and 來連接，意思沒有兩樣？

e.g. 　　1_1. She is nice and beautiful.
　　　　 2_1. Ted plays baseball and soccer.
　　　　 3_1. Sarah gave her sister a pen and a dictionary.
　　　　 4_1. We enjoy the movie and the time with our friends at a movie theater.

not only 和 but also 後所連接的詞，在詞性上要相同。（也就是說，not only 後所連接的詞為形容詞，則 but also 後所連接的詞，也要是形容詞。）

例：
5. John and Tom are students.（主詞有兩個人，所以是複數，be 用 are。）
6. The children and their dog like eating hamburgers. （主詞是複數，所以動詞 like 後面不需加 s。）

上述兩個例句若改為用 not only ... but also ... 連結，其結果就會有變化：

例：
5_1. Not only John but also Tom is a student.
　 （主詞看起來雖是有兩個人，但其實只算 but also 後的那一個，所以 be 用 is，且 students 改用 a student。）
6_1. Not only the children but also their dog likes eating hamburgers.

在例句 6 中，因為主詞是「複數」，所以動詞 like 後面當然不可加 s；但例句 6_1 顯然是不同的，like 後加了 s，由此可推知，當 not only A but also B 放在「主詞」的位置時，在現在式中，其後的動詞，是要看 B 決定單、複數。