【单选题】在铁路网中起联络、辅助作用的是哪一级铁路?
【简答题】在等比数列{a n }中,若公比q=m,前3项的和等于21,则该数列的通项公式a n =______.
【简答题】A.They have been hospitalizeded. B.They have got skin problems. C.They were choked by the thick smoke. D.They were poisoned by the burning chemical.
【单选题】They have been gathering this year's crop. They have been ____.
【简答题】在等比数列{a n }中,若公比q=4,前3项的和等于21,则该数列的通项公式a n =______.
【判断题】轴心受拉构件的刚度限制比轴心受压的刚度限制更严格。( )
【判断题】热力膨胀阀开启度小,会导致吸气温度过低。( )
【判断题】变速器异常响声现象,可能是由于变速器内部齿轮磨损过大引起的。
【判断题】中和10mL 0.1mol/L HCl和10mL 0.1moL/L HAC所需0.1mol/L NaoH溶液的体积相同。