石油及其产品在一定的温度下能蒸发大量的蒸气。当这些油蒸气与空气混合达到一定比例时,遇到明火即发生爆炸。这一类爆炸称为()爆炸。
A.化学性
B.物理性
C.超压
D.超温
参考答案:A
Speaker A: I can't seem to find a color TV of the new model. Speaker B:_____
A.Why don't you try the new store on King's Road
B.There's also something wrong with my TV set.
C.Don't you know the new model you want is not on the market yet
D.The new model is far more expensive than those old ones.
网络管理系统的功能是什么?()
A、提高网络性能
B、排除网络故障
C、保障网络安全
D、实现业务开通