【单选题】There is _____ with my eyes.I can't see clearly. [ ]
【单选题】The writer doesn't need to see the doctor because he eats an on- ion every day.
【单选题】用恒流源取代长尾式差动放大电路中的发射极电阻,将使单端电路的 ( )
【简答题】RNA 聚合酶是转录过程中所必需的,原核生物(以大肠杆菌为例) RNA 聚合酶有哪些组成成分?各个亚基的作用如何?
【多选题】在混凝土配合比设计中,水灰比的大小,主要由( )等因素决定。[2分][5分]