倾斜角为60°的直线的斜率为______．
因为直线的倾斜角为60°，所以直线的斜率k=tan60°=3．
故答案为：3．
She devotes herself _______________ , and makes it her life. [ ]
A. to teach
B. to teaching
C. teach
D. teaching
下列关于氨气的说法正确的是
A．氨气可以用浓硫酸干燥也可用碱石灰干燥
B．氨水能导电，所以NH3是电解质
C．稳定性：NH3＜CH4
D．用水吸收NH3用上图装置可防止倒吸
