下列哪种拭子采样，可能会使病毒灭活（）
A、植绒拭子
B、涤纶拭子
C、棉花拭子
D、藻酸钙拭子
E、以上均不可能
参考答案：D
Rock-climbing is a breathtaking activity, very popular nationwide among young people, ______ cooperation as well as courage plays an important role.
A．who
B．where
C．which
D．of which
水平巷道或倾斜巷道中电缆悬挂间距不大于（）米。
A.0.5m
B.0.4m
C.0.3m
