问题 单项选择题

脊椎动物中有一种类型的肾呈小管状,分节排列,每一肾小管一端开口于体腔,开口处漏斗状,上有纤毛,在肾口附近有血管球,以过滤的方式把血液中的代谢废物排入体腔中,借助肾口纤毛的摆动,将体腔中的代谢废物收集入肾小管;另一端汇入一总导管。上述内容描述的是()

A.原肾

B.前肾

C.中肾

D.后肾

答案

参考答案:B

解析:

脊椎动物的肾脏有三种主要类型:前肾、中肾和后肾。脊椎动物在胚胎时期都有前肾,但只有鱼类和两栖类的胚胎时期前肾才有作用。前肾的位置靠近体腔的前段,由许多肾小管组成。肾小管的一端开口于体腔,开口处膨大成漏斗状,这就是肾口,可以直接从体腔内收集代谢废物。在肾口附近还有由毛细血管形成的血管球,它们利用滤过血液的方式把血液中的废物送入肾小管,肾小管的另一端与一个总的管道相连,这就是前肾导管,末端通到体外。故选B

考点:本题考查肾脏的结构和功能。

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)

阅读下面短文,掌握其大意,从每题所给的A、B、C、D四个选项中,选出最佳选项。

It was my first day at school. I felt __36__ and scared. I went to all my classes with no friends. I felt no one really __37___ me. I listened anxiously to all the lessons and waited for the lunch break. Then finally the bell __38____. It was time to get free of the uneasy atmosphere.

During the lunch I met a new friend who wore a hat, and __39___ I am Jewish, we got along well, and I was so __40___ when she said, “Sit with us, at our table.” She __41___   to the one next to the door.

So I __42___, and took my tray and was about to walk with her ___43__  the floor, when suddenly I felt a nudge. “Hey, I saw you on the bus,” said a __44__ girl in a long skirt. “I __45___ your Jewish star necklace. You should sit with us.”

At that moment I _46____ around, and to my surprise, I __47___ the nations of the world, isolated themselves. The Spanish only sat with Spanish, the Hindus __48___ with Hindus, the Russians with the Russians, and __49___ the Arabs with the Jews. That’s what I saw __50___ my own eyes.

Suddenly, I saw the reason why wars got started in the world. Everyone __51____ to their own kind. The lunchroom was a ___52___  of the world. Why was everyone so  __53___? I was puzzled.

But I wanted a change. Determinedly, I turned __54___ this tall girl, and went with my new friend. There was no enmity(敌意) in the room. I felt relaxed. I built a ___55__ between two worlds when I sat with those different from me. The whole world should get close, not apart.

36. A. nervous              B. happy               C. comfortable              D. sad

37. A. cared for             B. stared at           C. believed in          D. thought of

38. A. sounded              B. rang                      C. came                       D. cried

39. A. when               B. although        C. if                       D. while

40. A. disappointed     B. relieved                C. angry                         D. upset

41. A. went                   B. pointed           C. ran                          D. got

42. A. approved            B. allowed            C. permitted                      D. agreed

43. A. through              B. past                  C. across                      D. along

44. A. beautiful         B. tall                       C. short                    D. plain

45. A. find                   B. like                  C. see                          D. have

46. A. turned                B. looked            C. walked                    D. stepped

47. A. understood       B. recognized        C. noticed                    D. knew

48. A. always             B. still               C. normally               D. occasionally

49. A. also                   B. ever                 C. never                             D. even

50. A. through           B. in                       C. for                              D. within

51. A. stuck              B. turned                C. went                   D. walked

52. A. symbol              B. sign                 C. map                        D. view

53. A. lonely                B. blind                C. strange                  D. independent

54. A. on                      B. to                   C. down                             D. off

55. A. tie              B. bridge       C. friendship           D. relation

单项选择题