生产现场不得仓储存放易燃易爆物品，生产现场需要使用的油类应盛放在（）密闭的容器内。
A.木头
B.金属
C.胶质
参考答案：B
-Do you know how many counties_______ during his journey to Europe last month?
-Quite a few. He was warmly welcomed by the countries' leaders.
A．did President Xi visit
B．President Xi visited
C．has President Xi visited
D．President Xi has visited
电动潜油泵井机组运转，但产液量很少或不出液，其原因是（）。
A、电泵型号
B、油管漏失
C、叶轮磨损
D、工作电压不足
