问题 单项选择题

关于焦点的叙述,错误的是

A.实际焦点是电子撞击阳极靶面的面积
B.有效焦点是实际焦点在不同方位上投影
C.靶面上形成的焦点是正方形
D.焦点用无量纲的数字表示
E.近阳极端有效焦点小

答案

参考答案:B

解析:有效焦点是实际焦点在X线投照方向上的投影。

完形填空

第二节:完形填空(共20小题;每小题1分,满分20分)

阅读下面短文,掌握其大意,然后从31~50各题所给的四个选项(A、B、C和D)中,选出最佳选项。

One day a wealthy family went on a trip to the countryside. The father wanted to   26   his son how   27   people live,   28   they spent a day and a night in the farm of a very poor   29  .When they got back from their trip the father asked his son, “My dear son, how was the   30  ?” “very  31   , Dad!” answered the boy. “Did you see how poor people live?” the father asked. “Yeah!” answered the son. “And what did you learn?” asked the father. The son answered, “I saw that we have a dog at home, and they have four. We have a   32    that reaches to the middle of the garden and they have a stream that has no   33    . We have imported lamps(进口灯具) in the garden and they have the   34   . Our patio(天井) reaches to the front yard,   35   they have a whole horizon(旷野).” When the little boy was   36  , his father was speechless.

His son   37   , “Thanks Dad   38  showing me how   39   we are!” Isn’t it true that it all depends   40  the  41  you look at things? If you have love, friends, humor and a positive attitude(乐观的态度)   42   life, you’ve got everything! You can’t buy   43   of these things,    44   still you can have all the material possessions(财富) you can imagine, provisions(储备) for the future, etc. But if you are poor of spirit, you have nothing! Attitude is   45  ! Make a decision to have a good, positive and productive attitude every day!

26.A.show      B. give       C. send               D. tell

27.A.happy     B. sorrow          C. rich               D. poor

28.A.thus          B. so          C. therefore           D. when

29.A.house     B. home     C. family             D. room

30.A.journey  B. trip        C. stay               D. travel

31.A.bad     B. good      C. well               D. badly

32.A.river      B. lake       C. canal(运河/沟渠)      D. pool 

33.A.endless   B. ending          C. end                D. ended

34.A.sun           B. stars       C. planet            D. electricity light

35.A.yet     B. however     C. so                  D. though

36.A.finished  B. finishing    C. completed         D. completing

37.A.adding    B. added     C. saying             D. said

38.A.for     B. of          C. with               D. about

39.A.poor       B. rich       C. glad               D. happy

40.A.in      B. on         C. for                 D. about

41.A.method   B. manners     C. way               D. means

42.A.of      B. for         C. to                  D. at

43.A.nothing  B. any        C. some              D. everything

44.A.then          B. but        C. though                  D. so

45.A.anything B. nothing      C. everything         D. something

单项选择题 配伍题