The traditional distinction between the verbs enquire and inquire is that enquire is to be used for general senses of ‘ask’, while inquire is reserved for uses meaning ‘make a formal investigation’.
In practice, however, enquire, and the associated noun enquiry, are more common in British English while inquire (and the noun inquiry) are more common in American English, but otherwise there is little discernible distinction in the way the words are used. Some style guides require that only inquire or only enquire be used.
Could I enquire about your mother’s health?
She inquired about the library’s rare books collection.
Every enquiry is very welcome.
Adam helped the police with their inquiries.
Both words derive from the Old French enquerre, from a variant of the Latin inquirere, based on quaerere ‘seek’. The same root word can be seen in various modern English words, including acquire, require, conquer, quest, request, inquest, and question.
1. Do you mind me to ____ about your salary?
2. The police are ____ into the accident.
答案：1. inquire/enquire 2. inquire