【单选题】In a two-stroke engine the camshaft rotates at____ the engine rotational speed.
【多选题】下列类型黄酮在甲醇溶液中的UV光谱具有2个吸收带的是( )。
【简答题】检查某教学楼的自动喷水灭火系统时发现:最不利点的喷头处压力表显示工作压力为0.03Mpa,经放水测试,控制室联运控制器不显示水流指示器的动作信号,该系统约有3000只喷头,设有3个报警阀组,在水泵房检查发现喷淋泵的出水阀门被关闭。对关闭喷淋泵出水阀门的行为应当如何处理?
【单选题】My grandfather is such a forgetful person that he has to _______ many things, even his daily meals. [ ]
【判断题】数控机床刀具从机械手中脱落,排除故障时应更换卡紧销或弹簧。