Regulations require that cargo tanks carrying grades D or E liquids on tank barges be vented with（）. ["gooseneck vents and flame screens","pressure-vacuum relief valves","branch vent lines and a vent header","forced draft blower"]
为什么西亚常被称为“三洲五海之地”？它在国际交通和战略上有何重要意义？
焊点直线度的自检标准是（）。 ["<=3mm","<=2.5mm","<=2mm","<=4mm"]
亚共析钢的含碳量越高，其平衡组织中的珠光体量（） ["越多","越少","不变","无规律"]
下列属于中国古代神话故事有（）。 ["盘古开天地","嫦娥奔月","女娲补天","精卫填海","夸父追日"]
（）是烟草行业对国家应作的贡献，是行业的基础责任。
