题目

Knowing office rules — whether _______ or not—is critical, particular for young job seekers.    A. written    B. writing    C. being written   D. having been written 答案：A 解析: 略下图所示实验操作正确的是                           A．滴加液体       B．过滤           C．点燃酒精灯      D．稀释浓硫酸