如图所示,M、N是竖直放置的平行板电容器的两个极板,R0为定值电阻,R1、R2为可调电阻,用绝缘细线将质量为m、电荷量为 + q的小球悬于电容器内部。闭合开关S,设法让小球做小角度摆动,测得周期为T。调节R1、R2,关于该摆做小角度振动的周期的判断,正确的是(小球摆动时不会碰极板)
( )—_______is your toy car? —It’s under the desk.
( )—What does your uncle do? —_______.
连线。 Stand up!一定要努力学习! Do study hard!别迟到。 Don’t be late.当心! Hands up, please.起立! Look out!请举手。
下面的感叹句由How还是What引导? (1) fat he is!(2) fast she runs! (3) a lovely dog!(4) an interesting film! (5) nice the food is!(6) a good boy! (7) kind his mother is!(8) a nice camera it is! (9) clever students they are!(10) slowly the rabbits run!
_______in bed. It’s bad for your eyes.