49. What step is essential to the traditional production of flu vaccine?

44. Research into the material culture of a nation is of great importance because ________

7.The educational expert’s speech ________ a new round of consultation from parents about children’s domestic education.

54. A neighborhood was classified as a “slow” one when ________.

41. Professor began to give high grades in the early 1970s because _____

50. The foremost reason why the egg-based method is defective lies in ________

23.足球运动战术中，（ ）是指防守中本队一个队员被对手突破时，另一个队员前去封堵。

40.

11. ________ on the cyberspace issue in a speech at a welcoming dinner in Seattle, Xi Jinping called on all countries to cooperate and draw up Internet policies corresponding with their national conditions.

24.

47. What does Grace Kao say about interracial lodging?