If you require some information you can say: (来源：英语杂志 http://www.EnglishCN.com)

    Could you tell me if/when/how much/why...?

    I wonder if you could tell me...?

    I'd like to know...

    I'd like some information about...

    If someone asks you for information you can reply:

    As far as i know...

    Well,(in confidence,) i can tell you that...

    I'm afraid i don't know...

    I've no idea,I'm afraid...

    I don't have that information available just now,can i call you back?

    I'm not sure,I'll have to find out,Can i let you know tomorrow?

    I'm afraid i can't tell you that,it's confidentail.