运用数学模型，拟合一条趋势线，外推未来事物的发展，这种市场预测方法为（）。
A.指数平滑法
B.回归分析法
C.移动平均法
D.趋势外推法
参考答案：D
— Mark, please don't play basketball on the road. It's very dangerous.
— _____. I am going home at once. [ ]
A. Have a great time
B. Sorry, I won't do that
C. I'd like to
D. OK, with pleasure
能实现下列物质间直接转化的元素是（ ）
单质+氧气 →氧化物+水 酸或碱+NaOH或HCl 盐．
A．硅
B．硫
C．铜
D．铁
