split infinitive
noun [ C ] language specialized uk/ˌsplɪt ɪnˈfɪn.ɪ.tɪv/ us/ˌsplɪt ɪnˈfɪn.ə.t̬ɪv/
分裂不定式（指在 to 和动词之间插入副词或其他词，有些人认为这并非标准的语法）
a phrase in which an adverb or other word is put between "to" and an infinitive. Some people consider split infinitives to be bad grammar, but they are becoming generally acceptable
"To boldly go" is an example of a split infinitive. to boldly go 是分裂不定式的一个例子。