民用建筑的耐火等级分为()。
A.三级
B.四级
C.二级
D.五级
参考答案:B
解析:本题考查的是建筑物的耐火等级。民用建筑耐火等级分为一、二、三、四级。故本题答案为B。
Prices ________ all the time and no one knows when they ________ stable.[ ]
A.are going up; become
B.have been going up; will become
C.have gone up; will become
D.have been gone up; become
保税物流中心存放保税物货物没有时间限制。