问题 单项选择题 A1/A2型题

有关VP试验,哪种说法是错误的()

A.主要鉴别大肠埃希菌和产气杆菌

B.VP试验阳性时,产生黄色化合物

C.大肠埃希菌VP试验阴性

D.产气肠杆菌VP试验阳性

E.大肠埃希菌和产气杆菌均能分解葡萄糖产生丙酮酸

答案

参考答案:B

解析:VP试验的原理:某些细菌在糖代谢过程中分解葡萄糖产生丙酮酸,丙酮酸脱羧产生乙酰甲基甲醇,在碱性环境中乙酰甲基甲醇被空气中的氧氧化为二乙酰,进而与培养基中蛋白胨精氨酸所含的胍基作用,生成红色化合物,为VP试验阳性。

完形填空

Robeson was born in a very poor family.At seven,he had to pick coal in a deserted mine near his home,then he sold  26  he had picked and earned a few coins to help his parents.He had

  27  schooling,for being so poor,how could they   28   school fees?

When he was fifteen,he worked   29  a servant in a school.Looking at other children studying in the classroom,he felt  30  for himself.How he   31   to have the same chance!He decided to study by  32  .In the daytime,after the sweeping and cleaning was over,he   33  

stand by the window outside the classroom trying to catch what the teacher said.At night,he tried his best to remember what he   34  during the day.He worked   35  hard at his lessons that he sometimes had just three or four hours to sleep.The more he learned,the greater  36  he showed in his lessons.A maths teacher discovered him and came to like this diligent boy and  37  him to sit at the back of the class.In one exam,he was the  38  one in the whole school who reached the highest grade.He would have been given the scholarship if he   39  a regular student of the school.

Robeson  40  rough six long years with his study of maths and wrote several articles which captured the  41  of some university professors.They admired his talent  42  his diligence.To give him a good chance,they hired him as a librarian and  43   him free guidance.Robeson felt  44  ,for he was sure that before him there was a broad road   45  success.

26.A.whether                B.which                       C.that                           D.what

27.A.many                   B.few                           C.little                         D.much

28.A.buy                      B.afford                       C.send                          D.read

29.A.as                        B.like                           C.for                            D.by

30.A.angry                   B.ashamed                    C.proud                        D.sorry

31.A.hated                    B.decided                     C.wished                      D.regretted

32.A.the teacher            B.himself                            C.his parents                 D.his schoolmates

33.A.could                   B.ought to                    C.should                       D.would

34.A.had learned                                              B.has been taught

C.has heard                                                      D.had been written down

35.A.very                            B.so                             C.too                           D.quite

36.A.joy                       B.interest                      C.time                          D.taste

37.A.allowed                B.agreed                      C.let                                   D.refused

38.A.worst                   B.only                          C.last                           D.laziest

39.A.had been               B.has been                    C.is                              D.was

40.A.learned                 B.listened                     C.mastered                   D.struggled

41.A.notice                   B.influence                   C.eyes                          D.attention

42.A.except for             B.according to                     C.as well as                  D.in spite of

43.A.taught                  B.offered                      C.lent                           D.sent

44.A.sad                       B.angry                        C.happy                       D.disappointed

45.A.leading to             B.coming from             C.made of                    D.covered with

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