一张工作票下设（）小组的工作或工作票签发人（工作负责人）认为需要办理电力线路工作任务单的工作应填写电力线路工作任务单。
参考答案：多个
— When did you become a volunteer?
— Two years ago. I _____ this group since then. [ ]
A. joined
B. have joined
C. have been in
定期用（）将循环氨水槽底部聚集的焦油抽送至机械化氨水澄清槽。
