问题 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

答案

答案:C

完形填空

A teacher once told each of her students to bring a clean plastic bag and a bag of potatoes to school. For every person they didn’t want to forgive(原谅) in their lives, they chose a potato, wrote the person’s   1  and the date on it and put it in the plastic bag. Some of their bags were very   2 . They were then told to carry this bag with them   3  for one week. They would put it beside their bed at night, on the seat when sitting in a car or on a bus , and next to their desks at   4  . The   5  carrying the bag around with them made students get to know what a weight they were carrying in their minds. They had to pay attention to(注意) it all the time so that they wouldn’t  6  it or leave it in embarrassing(尴尬的) places. As time passed by, the potatoes went   7  and smelt terrible. Too often we think of tolerance(宽容) as a    8  to other people, but it clearly is for   9 ! If we choose to keep our sadness and hatred(仇恨) in our hearts, we will have to   10  them around all our lives.
小题1:
A.ageB.nameC.hobbiesD.weight
小题2:
A.smallB.beautifulC.lightD.heavy
小题3:
A.everywhereB.nowhereC.somewhereD.where
小题4:
A.homeB.workC.nightD.school
小题5:
A.studentsB.daysC.potatoesD.teachers
小题6:
A.forgetB.buyC.rememberD.find
小题7:
A.bigB.wrongC.badD.good
小题8:
A.feelingB.wasteC.giftD.greeting
小题9:
A.themselvesB.ourselvesC.yourselfD.itself
小题10:
A.missB.meetC.carryD.enjoy
问答题