成人英语三级考试

【单选题】First aid can save a person's life if ______ immediately and properly.


A．perform
B．performing
C．performed
D．to perform

网考网参考答案：C
网考网解析：
[考点] 状语从句中的省略 [解析] 补充完整的从句为if first aid is performed immediately and properly。 查看试题解析出处>>