调速范围满足一定的静差率条件，同理，静差率是在满足一定的调速范围条件下讲的。
参考答案：对
若方程x3-x+1=0在区间(a，b)(a，b∈Z，且b-a=1)上有一根，则a+b的值为[ ]
A．-1
B．-2
C．-3
D．-4
This coat doesn't fit me. Could you show me one? [ ]
A.other
B. another
C. others
D. the other
