用于表示流水施工在施工工艺上展开顺序及其特征的参数是（）。
A．施工段
B．施工层
C．施工过程
D．流水节拍
参考答案：C
有一组多项式：a+b2，a2-b4，a3+b6，a4-b8，…，请观察它们的构成规律，用你发现的规律写出第10个多项式为____________.
Food supplies in the flood-stricken area _______. We must act immediately before there’s none left.
A．have run out
B．have been run out
C．are running out
D．are being run out
