拆除区域周围应设围栏并悬挂安全标志牌，派专人监护。无关人员和车辆不得（）。
参考答案：通过或停留
_______ of danger in the street at night, she had to go home, with a friend ______ her.
A．Warning; following
B．Having warned; followed
C．Having been warned; following
D．Warned; followed
简述激光扫描共聚焦显微镜的结构特点及其在医学领域的主要用途。
