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。