Don't eat the noodles___________ your hands. Here you are. The chopsticks.
A:about
B:for
C:of
D:with
I got a beautiful gift on birthday.
两根足够长的平行光滑导轨竖直固定放置,顶端接一电阻R,导轨所在平面与匀强磁场垂直.将一金属棒与下端固定的轻弹簧的上端拴接,金属棒和导轨接触良好,重力加速度为g,如图所示.现将金属棒从弹簧原长位置由静止释放,则( )