为什么看火眼压力为什么不宜过大或过小？
下面描述有关播放PowerPoint演示文稿的控制方法，其中（）是错误的。 ["可以用键盘控制播放","单击鼠标右键，可以定位到任意一张幻灯片","可以用鼠标控制播放","不能用“↑”或“↓”键切换到“上一张”或“下一张&rdquo"]
The main purpose of the piston oil scraper rings is to （）. ["seal the space between the piston and the liner","reduce the amount of lube oil burned in the combustion chamber","transmit heat from the piston to the cylinder liner","damp out fluctuations of the piston side thrust"]
酸性土壤中生长的植物容易出现哪些元素毒害现象？（） ["铁","锰","镁","钙"]
A shipmate suffers a heart attack and stops breathing. You must（）. ["administer oxygen","immediately check his pulse and start CPR","make the victim comfortable in a bunk","immediately give a stimulant，by force if necesssary"]
小透平组跳闸（或全停交流电），透平岗位该如何处理？
