[问答题] 关闭阀门时应怎样操作？

离子键 HIV的传播途径有（） ["性接触","注射","母婴","人工授精","与感染者握手"] 呈慢性复发性头痛的是（） ["椎-基底动脉供血不足","鼻源性头痛","肌收缩性头痛","偏头痛","急性青光眼"] 头痛病因中属颅外疾病的是（） ["偏头痛","三叉神经痛","神经衰弱","癔症","中暑"] 属于《医疗机构制许可证》许可事项变更的是（） ["法定代表人变更","医疗机构类别变更","注册地址变更","配制地址变更"] 关闭阀门时应怎样操作？