41. During her study in Massachusetts Institute of Technology she has got the degree _____ PhD, and it is a degree ______ chemistry.

42. In China children, even in their twenties depended _____ their parents _____ food and clothing.

43. Our national scenery Zhangjiajie is so charming that it is _____ description.

44. _____ the _____ of modern industry, the pollution is becoming more and more serious.

45. The twins look much like each other, but they are different _____ nature.

46. _____ his disadvantage, it began to rain heavily suddenly.

47. She was disappointed _____ hearing the news that Chinese football team lost the first match in “World Cup”.

48. Some new changes happened _____ the school _____ my absence.

49. He goes _____ at 8 a.m. and comes _____ at 5 p.m. Today he is _____.

50. The Englishman has a very good ear _____ music. You can ask him for some advice.