Why is the ring belt narrower in diameter than the skirt of a piston designed for a diesel engine?（） ["To allow for greater expansion due to higher operating temperature","To seal the cylinder against leakage of combustion gases","To provide an additional surface for oil cooling","To provide an additional strength for the crown and lower structure"]
由许多提供相同产品和服务的企业所组成的行业之间的竞争被称为（） ["差异优势竞争","完全垄断","垄断性竞争","完全竞争"]
在市场预警制度中，对（），依法予以处理，将处理结果记入“经济户口”管理档案。 ["公告警示后未能及时整改","继续从事违规违章行为的","整改效果不明显的","及时整改","公民或社会组织的监督制度"]
The effective pump stroke of an individual port-and-helix fuel injection pump is determined by the （） ["fuel delivery pressure","pump plunger diameter","plunger control rack position","total pump stroke"]
兴奋在神经纤维上的传导过程是通过细胞膜内外两侧电位瞬间变化（由外正内负变外负内正，再变回外正内负）的传导实现的，膜内外两侧电位的瞬间变化是通过下列哪一项实现的（） ["Ca2+<\/sup>的跨膜主动运输","K+<\/sup>的自由扩散","载体蛋白对Na+<\/sup>、K+<\/sup>等的协助扩散","离子通道对Na+<\/sup>、K+<\/sup>等的协助扩散"]
镜架的校配一般包括哪些方面？
