It was very late. The mall was _____. [ ]
A. open
B. opened
C. close
D. closed
答案:D
快速卸荷阀(也称压力调节阀),用于()。
飞机加油车灌油岛用的灌油接头和胶管的检查标准是()。
A.不渗漏
B.转动灵活、无卡阻
C.无龟裂、无老化、无磨损、无起泡
D.以上都是