--- The floor is dirty. Can anyone clean it?
--- ______. I do it all the time.
| A．Don’t mention it | B．Why you? | C．Not sure. | D．Not me again. |
51. Don’t put your cell (手机) _____ the edge of the table, or it will fall off
| A．at | B．on | C．to | D．In |
50. The Englishman has a very good ear _____ music. You can ask him for some advice.
| A．at | B．of | C．for | D．In |
49. He goes _____ at 8 a.m. and comes _____ at 5 p.m. Today he is _____.
| A．on duty; off duty; on night duty | B．on his duty; off the duty; on night duty |
| C．to duty; from duty; at night duty | D．in duty; out duty; at night duty |
48. Some new changes happened _____ the school _____ my absence.
| A．at; to | B．in; for | C．in; during | D．at; on |
47. She was disappointed _____ hearing the news that Chinese football team lost the first match in “World Cup”.
| A．at | B．in | C．of | D．With |