如果没问就别说。如果问了，就这样

如果你现在在政府或公共大公司，且面试对等的单位，就说：I am not sure it's entirely appropriate, but perhaps it's a common knowledge any way, my role and responsibility get paid between xxx to xxx (give a 10%range).

如果你现在在私人或公共小公司，且面试对等的单位，就说：I am not sure it's appropriate, but put in this way, I think based on my role and responsibility, would I be getting something between xxx to xxx? My current earning is not far different from that (give a 20% range).

如果你面试不对等的单位或不对等的职位，基于上述情况作些变通。关键在于表现出尊重原雇主由不得罪新雇主。至于讨价还价余地，与这个其实关系不大。