为了同学们饮水安全、卫生,学校要安装一台电热水器,该电热水器的额定电压是380V,额定功率是15kW,连接该电热水器时,有四种绝缘铜芯导线供选择,其规格如表所示,从既安全又经济的方面考虑,选用导线的横截面积是
导线规格
导线横截面积S/mm2
2.5
4
6
10
安全载流量I/A
28
37
47
68
A:2.5mm2
B:4mm2
C:6mm2
D:10mm2
——Hello! Would you like to go to the party with me tonight?
——I'm sorry I can't . Mother won't ______me to go out in the evening.
肺的结构与呼吸功能相适应,与此无直接关系的叙述是( )
二次函数y=﹣(x﹣1)2+3的图象的顶点坐标是( )