During the race many cars ______ while m_爱下问搜题

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问题选择题

During the race many cars ______ while my new solar car came out first.

A．broke out

B．broke away

C．broke down

D．broke up

答案

答案：C

选择题

— How was the party?

— I don't know. I ________ in without a ticket. [ ]

A. was allowed

B. was not allowed

C. am allowed

D. am not allowed

选择题

如图所示，在x轴上方存在着垂直于纸面向里、磁感应强度为B的匀强磁场，一个不计重力的带电粒子从坐标原点O处以速度v进入磁场，粒子进人磁场时的速度方向垂直于磁场且与x轴正方向成120°角，若粒子穿过y轴正半轴后在磁场中到x轴的最大距离为a，则该粒子的比荷和所带电荷的正负是（　　）

A．，正电荷

B．，正电荷

C．，负电荷

D．，负电荷