【简答题】一观察者静止于铁轨旁 , 测量运行中的火车汽笛的频率。若测得火车开来时的频率为 2010 Hz, 离去时的频率为 1990 Hz, 已知空气中的声速为 330m .s -1 , 则汽笛实际频率 是 。。。
【多选题】中国证监会部署开展“2015i证监法网专项执法行动”,这意味着()
【简答题】一观察者静止于铁轨旁 , 测量运行中的火车汽笛的频率.若测得火车开来时的频率为 2010 Hz, 离去时的频率为 1990 Hz, 已知空气中的声速为 330 m.s -1 , 则汽笛实际频率 n 是 .
【单选题】We live on the top floor,________has really high celling and skylights.
【单选题】We hold them up to the standards we see in our top people.
A.
We compare them with the top people and see if they have the same traits.
B.
We evaluate them according to the qualities we see in our top people.
C.
We put up with them because they show the standards of top people.
D.
We regard them as the standards for recruiting top people.
【单选题】应变片的选择包括类型的选择、材料的血案则、尺寸的选择和( )等
【判断题】修理车间必须备有充足的消防器材并符合当地消防规定,消防器材附近不得放置任 何影响器材使用的物品 () ()