A:Happy and excited
B:Happily and excited
C:Happily and excitedly
D:Happy and excitedly
方程2x2﹣5x+3=0的根的情况是( )
如图所示,轻弹簧两端拴接两个质量均为m的小球a、b,拴接小球的细线固定在天花板,两球静止,两细线与水平方向的夹角α=30°,弹簧水平,以下说法正确的是( )