such heavy pollution already, It may now be too late to clean up the river.
49. He goes _____ at 8 a.m. and comes _____ at 5 p.m. Today he is _____.
48. Some new changes happened _____ the school _____ my absence.
47. She was disappointed _____ hearing the news that Chinese football team lost the first match in “World Cup”.
46. _____ his disadvantage, it began to rain heavily suddenly.
45. The twins look much like each other, but they are different _____ nature.