题目

The workers agreed to ________ the strike if the company would satisfy their demands.        A. call for                    B. call in                      C. call off                     D. call up 答案：C 解析: 略使用显微镜时，要在目镜中看到自亮的圆形视野，关键的步骤是 ( )A．对光B．使用高倍显微镜C．清洁载玻片D．标本染色