问题 名词解释

侵蚀基准面

答案

参考答案:

河流下切深度并不是无止境的,往往受到某一基面的控制,河流下切到这一基面后,就不再向下侵蚀,这一基面称河流侵蚀基准面。海平面是控制外流河向下侵蚀的下限,这一控制河流下蚀的最低基准面称为终极侵蚀基准面。湖盘、干支流交汇处、坚硬岩坎甚至堤坝,也可成为句地的或暂时的基准面。

单项选择题
完形填空

阅读下面短文, 掌握其大意,然后从36~55各题所给的四个选项(A、B、C和D)中,选出最佳选项。

One day before Christmas, all of us children from the Children's Home Society Orphanage(孤儿院) were taken to the Mayflower Hotel in downtown to attend a Christmas party.

After the man on the stage said a prayer      (祈祷), we were told to  36  . Within minutes we were   37   a meal which was fit for a king. I ate   38 I could eat no more. As we ate, Santa Clause came walking out onto the  39 . The kids cheered with  40 . Everyone began clapping their hands and yelling as   41 as they could.

I too was excited   42  but I knew better than to yell(叫喊)out loud or to jump up and scream. Mrs. Winters, the head matron, sat only three seats from me. She had   43  it very clear to everyone that we were tobehaveourselves in "a proper manner" and that there was to be "no yelling or shouting".

One orphan   44 was led up onto the stage and each kid was handed a   45  by Santa Claus himself.

As the line became shorter and shorter my   46  finally came. He smiled at me. Then he reached over and handed me a   47  box which had two gold ribbons(丝带) on it. As I leaned(向前倾) to take the box I tripped and I   48 to my knees. Santa reached over and helped me to my feet.

"Move  49  Kiser." called out Mrs. Winters.

I was now leaning against Santa Claus' leg and I was looking   50  into his eyes. His face was less than an inch from mine.

"Can I   51  you Santa?" I asked him.

The next thing I knew Mrs. Winters had caught me up by my shirt collar and was  52  me away from the line of children.

I sat down in my chair just crying. Once in a while I would  53  at the stage to see if my gift was still sitting by Santa Claus.

When we all lined up waiting, I  54 "HO HO HO" coming from behind me.

As I   55 , there stood Santa Claus holding my large box. Then he knelt down and he hugged my neck as hard as he could.

36. A. stand up           B. go out               C. sit down            D. keep silent

37. A. taken               B. served               C. brought             D. supplied

38. A. until                  B. unless               C. before               D. after

39. A. table                   B. hotel                 C. seat                   D. stage

40. A. encouragement  B. excitement        C. disappointment D. astonishment

41. A. loud                  B. big                   C. high                  D. low

42. A. outside               B. beside              C. aside                 D. inside

43. A. took                  B. made            C. demanded         D. warned

44. A. at a time          B. at one time        C. at time’s            D. at time

45. A. favor                      B. box                C. gift                  D. medal

46. A. turn                   B. way                 C. chance              D. gift

47. A. golden                      B. yellow              C. small                D. large

48. A. sat                     B. fell                  C. dropped            D. turned

49. A. by                     B. on                 C. in                    D. out

50. A. quickly            B. directly            C. immediately      D. finally

51. A. tell                            B. call                  C. hug                  D. leave

52. A. pushing              B. keeping             C. stopping            D. pulling

53. A. look                 B. jump              C. put                 D. stand

54. A. watched           B. found               C. heard                      D. observed

55. A. turned around      B. turned up          C. turned away       D. turned down