Following a grounding, you can best determine that a SLACK fuel oil tank has been holed by （）. ["sounding the tank","waiting for the vessel to list","examining tank boundaries","checking fuel oil strainer"]
设立认证机构，注册资本不得少于（） ["50万元","100万元","200万元","300万元"]
如果发动机运转时正时皮带突然断裂，弯曲变形的零件通常为（）。 ["凸轮轴","连杆","气门"]
下图是属接触器的（）控制线路。 ["点动","点、连动","自锁","一般开关"]
北美洲的植被―土壤类型在组成上有何特点？产生这些特点的原因是什么？
北美洲的植被―土壤类型在分布上有哪些特点？
