电视机的中频放大器通频带约为（） ["10mhz","6mhz","2mhz"]
下图为西藏南迦巴瓦峰地区垂直自然带谱示意图。
据上图所知，下列说法正确的是（） ["南坡雪线低，是因为南坡气温低，降水多","北坡自然带种类少，是因为北坡降水少","南坡山谷地区是热带季风气候","南坡自然带分布范围都比北坡小"]
已知一正弦电流，t＝0时的瞬时值i0＝O.5A，并已知初相角为30°，求其有效值是多少？
RADSS型母差保护屏上有哪些信号？
In a diesel engine, when the fuel is injected into the cylinder,（） ["the piston is just coming upward from the bottom dead center","the piston has moved about one-fifth of the way up","the piston has moved most of the way up and almost reached the TDC","the piston has just past the TDC"]
RADSS型220kV母差保护在倒母线的操作过程中运行方式如何？
