我们做了一份关于镇上图书馆的读者调查 We did a survey of our readers ___ lidraries in our town
问题描述：
我们做了一份关于镇上图书馆的读者调查 We did a survey of our readers ___ lidraries in our town
答
We did a survey of our readers _using/patronizing__ libraries in our town