水尺的零刻度线相对于某一基面的高程即为（）。
A、水尺零点高程
B、水尺零点高度
C、水尺高程
D、水尺零点高差
参考答案：A
--- Nancy, can I take a look at the note you took for last period, please?
--- I’m sorry, I __________ something else then. I’ll make it up right away.
A．did
B．was doing
C．had done
D．have done
简述促成和抑制栽培主要哪些途径。
