砂垫层施工控制的关键主要是:
A.虚铺厚度
B.最大干密度
C.最优含水量
参考答案:A, B, C
. In our country, it’s a practice that workers have _____ for the Spring Festival.
A.a week off
B.a week’s off
C.a weeks’ off
D.a week leave
心理健康就是无失败、无冲突、无痛苦。( )