小明在探究“小灯泡发光时的亮度与电功率的关系”的实验中,所用的电源电压是4V,小灯泡的额定电压是2.5V,小灯泡两端允许加的最大电压为额定电压的1.2倍。
A:Would you mind my smoking here?
B: ______. Look at the sign. It says" No smoking."
I usually get up early ______ the morning.
造成“世界屋脊”和“鱼米之乡”农业生产差异的根本原因是( )