She sells things, she is a / an _____________. [ ]
A. salesperson
B. artist
C. teacher
答案:A
软弱围岩隧道IV、V、VI级地段采用台阶法施工时,上台阶每循环开挖支护进尺V、VI级围岩不应大于()钢架间距。
氟化钠溶液每日含漱一次的浓度为
A.2.0%B.0.2%C.0.5%D.1.0%E.0.05%