起重钢丝绳，安全系数是（）
A、4-5
B、5-6
C、8-10
D、17
参考答案：B
Though there are some differences in American education and Chinese education, both systems
are ______ excellent graduates. [ ]
A. turning away
B. turning off
C. turning in
D. turning out
发酵过程工艺控制的只要（）溶解氧、PH、核酸量等
