操作系统是一套（）程序的集合。 ["文件管理","中断处理","资源管理","设备管理"]
Generally speaking，the fuel injected into a marine diesel engine combustion chamber is ignited by（）. ["spark plugs","glow plugs","heat of compression","a magneto"]
Before marine sewage treatment plant works （） should be filled with fresh water. ["deposition chamber","oxidation pool","disinfection chamber","all chamber"]
将下面的景观分为两类，并写出其名称。
网络计划方法的步骤有（）。 ["A.项目分解","B.确定各种活动之间的先后关系","C.估计活动所需的时间","D.计算网络参数，确定关键路线","E.优化、监控、调整"]
水稻幼苗时，叶片与稗草非常相似，一样具有长扁型的外观，大多根据稻叶特殊的（）与（）来区分。
