混凝土从装料到入仓卸料整个过程不宜超过（）。
A.15～20min
B.20～30min
C.30～60min
参考答案：C
Don't_________about things so much. It will make you stressed out. [ ]
A. afraid
B. terrify
C. terrified
D. worry
氛围调整法
