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

第二节.完形填空:(共20小题,每小题1.5分,满分30分)

On Christmas Eve, I gave each of the children three pieces of stationery (文具) with envelopes.At the (36) of each page were the (37), “What I love about my sister Mia”, “What I love about my brother Kris”, “What I love about my sister Lisa” and “What I love about my brother Erik”.The (38) were 16,14,10 and 8, and it (39) some time to make it clear to them that they could find just one thing they (40) about each other.As they wrote in privacy, I went to my bedroom and wrapped their few store-bought (41).

When I returned to the kitchen, the children had finished their (42) to one another.Each name was written on the outside of the envelope.We (43) hugs and goodnight kisses and they hurried off to bed.Lisa was given special (44) to sleep in my bed, with the promise not to steal a (45) at the gifts until Christmas morning.

Early in the (46), we all got up and sat around the tree and opened the few wrapped presents.(47) the children were given their (48) envelopes.We read the words with (49) eyes and red noses.Erik, at 8, wasn’t expecting to hear anything (50).His brother had written: “What I love about my brother Erik is that he’s not (51) of anything.” Mia had written, “What I love about my brother Erik is that he can talk to (52)! “Lisa had written.“What I love about my brother Erik is that he can (53) trees higher than anyone!”

I felt a gentle pull at my sleeve, and then a small hand cupped around my ear and Erik “(54), “Gee, Mom, I didn’t (55) know they like me!”

36.A.top    B.end   C.middle      D.side

37.A.phrases     B.sentences  C.words       D.demands

38.A.boys  B.girls  C.daughters  D.kids

39.A.spent B.took  C.cost   D.paid

40.A.liked B.talked       C.hated D.learned

41.A.products   B.clothes      C.gifts  D.flowers

42.A.homework       B.thanks      C.tasks  D.letters

43.A.exchanged       B.spared      C.enjoyed    D.attempted

44.A.order B.permission       C.request     D.duty

45.A.notice       B.watch       C.look  D.note

46.A.evening    B.moon       C.afternoon  D.morning

47.A.Afterwards      B.Therefore  C.However   D.Fortunately

48.A.two   B.three C.four  D.many

49.A.sad    B.bright       C.teary D.happy

50.A.strange     B.funny       C.nice   D.terrible

51.A.sure  B.certain      C.kind  D.afraid

52.A.anybody   B.somebody C.nobody     D.teachers

53.A.feel   B.climb       C.reach D.touch

54.A.shouted    B.cried C.whispered D.screamed

55.A.ever  B.yet    C.never D.even

单项选择题