执勤中队执行任务后,必须()及时对使用过的装备器材进行一次维护保养。
参考答案:每周
The hospital _________ well, where many wounded ________every day. [ ]
A. is operated; operation
B. operates; are operated on
C. operates; are operated
D. operates; operates on
天然饰面石材中,大理石板材的特点是下列表述中的()。
A.吸水率大,耐磨性好
B.耐久性好,抗风化性能好
C.吸水率小,耐久性差
D.耐磨性好,抗风化性能差