深井泵叶轮轴与橡胶轴承间隙应保持在（）毫米之间。
A、0.05～0.1
B、0.15～0.2
C、0.2～0.4
D、0.4～0.6
参考答案：C
This is just between you and me. You _________ tell anyone about this. [ ]
A. mustn't
B. can
C. should
D. have not to
银行为刘小姐提供的最长免息还款期为( )天。
A．49
B．40
C．60
D．52
