1954年,我国地质探矿队伍发现,在山东某地一面积约4万平方公里地区的地磁场十分异常。据此,勘探队伍推测该地区地下可能蕴藏着[ ]
A.铜矿
B.铁矿
C.煤矿
D.石油
答案:B
The prototyping method is a dynamic design processes, which requires people who use prototyping method to have the following capability of ().
A.proficient program expertise
B.immediately acquire requirement
C.coordinate organize eloquently
D.handle tools smartly
阀门研磨的质量标准是:阀头(阀芯或阀板)密封面部分应接触良好,表面无麻点、沟槽和()等缺陷,接触面应为阀座台宽的()。