a、b为两个带等量正电荷的固定的小球,O为ab连线的中点,如图所示,c、d为中垂线上的两对称点且离O点很近,若在C点由静止释放一个电子,关于电子的运动,以下叙述正确的有
﹣﹣﹣You _______ take photos here!Look at the sign.It says"No photos".
﹣﹣﹣ Sorry,I won't.( )
A.mustB.needC.mustn'tD.needn't
﹣﹣﹣Our class won the first prize in today's basketball match.
﹣﹣﹣_______ exciting news it is!We're all glad about it.( )
A.WhatB.What anC.HowD.How an
﹣﹣﹣Shall we go out and do some outdoor activities?
﹣﹣﹣_______.( )
A.You're welcome
B.That's a good idea
C.Don't worry
D.It's none of your business
Paper is ________ useful invention.It was invented around 2,000 years ago by Cai Lun.( )
A.aB.anC./D.the
﹣﹣Shall we go for a walk?
﹣﹣_____________.It's too dark.We'd better stay at home.( )
A.Nice ideaB.That's true
C.Don't be sillyD.I agree with you