压缩器失速已经发展并稳定的特征是什么？
参考答案：
严重的抖动和高的咆哮声。
减速箱的作用是()
A.增大能量
B.降低转速
C.增大转矩
D.减少转矩
Which of the following statements about hypothesis testing is TRUE A Type Ⅱ error is the probability of:（）
A. rejecting a true null hypothesis.
B. rejecting a true alternative hypothesis.
C. failing to reject a false null hypothesis.
