South Africa's leading stainless steel foundry group Steloy Castings recently delivered the first two of 30 diffuser bowls cast in ASTM A890 grade 6A (Super Duplex Stainless Steel), destined for a desalination plant in the Middle East. With a fettled mass of 1230kg each, challenging configurati...
19世纪80年代 **答案**: B **分析**:正确答案:B 解析:中国工人阶级最早出现于19世纪40至50年代外国资本主义在华企业中,如船舶修造业、出口加工业和口岸码头等。B选项正确。 知识模块:反对外国侵略的斗争 ©2024 Baidu |由 百度智能云 提供计算服务 | 使用百...