答案：C
In these years, the shortages of water has become a ______ problem.
A．global
B．historical
C．chemical
D．local
手选带式输送机的带速不得超过0.3m/s，倾角不得大于（）°。输送带宽度超过0.8m时，应当在两侧分别设手选台。
A.12
B.20
C.25
D.35
