Ⅰ. ask “问、询问”是最普通的用语，通常表示只是为了获得回答或了解某事而提问。如：
① I asked him if he could come. 我问他能不能来。
② I’ll ask him how to get there. 我要问他怎样去那儿。
Ⅱ. inquire “问、询问”表查究，调查的意思。如：
① I have inquired of him whether he could help me. 我已问过他是否能帮助我。
② She came to inquire about her friend’s health. 她来询问她朋友的健康情况。
③ He inquired of me about our work. 他向我了解了我们的工作情况。
Ⅲ. question “询问、审问、提问”含有提出一连串问题的意味。如：
① I questioned him about the matter.我问过他这件事。
② He was questioned by the police. 他受到警察的审问。