【单选题】He is believed to have been shot by a rival gang in ______ for the shootings last week.
【判断题】通过账户的对应关系,可以了解经济业务的内容及其内在联系 ( ) 。
【单选题】有压管道的管径D与管流水力半径的比值D/R=( )
【单选题】He is believed _______ the college exam, for he is now studying xery hard.
【单选题】当变压器和电动机合并成组时,电流速断保护的动作电流应按( )来进行整定。