与X线的产生无关的因素是（） ["A、电子源 ","B、高真空度 ","C、高压电场 ","D、电子的骤然减速 ","E、阳极散热"]
药物经生物转化后，总的效果是 ["A．药物水溶性降低","B．药物活性的升高","C．药物极性和水溶性降低","D．药物的极性升高，有利于排泄","E．药物的极性降低，有利于吸收"]
乳酸脱氢酶是由H、M亚基组成的 ["A．二聚体","B．三聚体","C．四聚体","D．五聚体","E．六聚体"]
组成LD2同工酶的四聚体为 ["A．H4","B．M4","C．H3M","D．HM3","E．H2M2"]
下列各项心肌标志物分子量最大的是 ["A．Mb ","B．CK-MB ","C．LDH ","D．cTnI ","E．AST "]
矿井供电系统中，《规程》规定矿井电源线路上严禁装设（）；严禁井下变压器的中性点（）。
