下列控制声音传播的措施中()不属于吸声措施。 ["A、用薄板悬挂在室内","B、用微穿孔板悬挂在室内","C、将多孔海绵板固定在室内","D、在室内使用隔音罩"]
根据《土地管理法》修正后的征收对象是农民集体所有的土地,在是否有偿的问题上,正确的是()。 ["征购是无偿的","没收是无偿的","征收是无偿的","没收是有偿的"]
(2010)一管径d=50mm的水管,在水温t=10℃时,管内要保持层流的最大流速是:(10℃时水的运动黏滞系数μ=1.31×10-6m2/s)() ["0.21m/s","0.115m/s","0.105m/s","0.0525m/s"]
苏木中易被氧化成红色的成分是() ["A.巴西苏木素","B.原苏木素A","C.苏木酚","D.挥发油","E.黄酮类"]
原始凭证按其取得来源,可分为外来()和自制原始凭证 ["A、原始凭证","B、记帐凭证","C、转帐凭证","D、票据"]
变压器应有(),并标明运行编号和相位标志。