[问答题] 简述原虫病的危害。

For a given size engine, the two-stroke/cycle diesel engine will deliver more power than a four-stroke/cycle diesel engine because （）. ["it has a longer power stroke","more air gets into the cylinder each stroke","it develops twice as many power strokes at the same speed","higher combustion pressure is developed"] 根据萨柏的职业生涯发展阶段理论，属于选择安置阶段的是（）。 ["衰退阶段","探索阶段","确立阶段","维持阶段"] 简述销售渠道财务分析方法的种类？ 装煤水分增加1％，火道温度应提高（）℃。 ["12.5","15","6"] 在PowerPoint 2003中，幻灯片母版上有几个占位符来确定幻灯片母版的版式？（） ["5","3","4","6"] 简述原虫病的危害。