The nurse is caring for a client admitted to the hospital with a bowel obstruction. The nurse should wear sterile gloves when （）.

A．inserting an indwelling urinary catheter.

B．giving a back rub on intact skin.

C．changing an oxygen system.

D．inserting an IV catheter.

在线路带电情况下，砍伐靠近导线的树木时有何要求？