如图所示,是一种娱乐设施“魔盘”,而且画面反映的是魔盘旋转转速较大时盘中人的情景。甲、乙、两三位同学看了图后发生争论,甲说:“图画错了,做圆周运动的物体受到向心力的作用,魔盘上的人应该向中心靠拢”。乙说:“图画得对,因为旋转的魔盘给人离心力,所以人向盘边缘靠拢”。丙说:“图画得对,当盘对人的摩擦力不能满足人做圆周运动所需的向心力时,人会逐渐远离圆心”。这三位同学的说法应是( )
Anna is preparing for the coming exam, so she has to ____ the invitation to the party.( )
A.turn onB.turn downC.turn offD.turn up
____ have you talked with your friends on the phone?
Since I finished my homework.( )
A.How farB.How oftenC.How soonD.How long
Oh, dear! I can't find my key to the office.
Don't worry. I think you might ________ it in your car.( )
A.offerB.forgetC.borrowD.leave
Jerry will succeed in working out the problem ____ he gives up.( )
A.IfB.becauseC.soD.unless
We will have a sports meeting in October, but ______knows the date for sure.( )
A.everybodyB.nobodyC.anybodyD.somebody