根据以下材料，回答题
Alice : Excuse me, Mr.Green.I' d like to take a few days off.
Green :     51     ?
Alice:My mother is ill.I have to take care of her.
Green:Oh dear! I am sorry to hear that.    52     ?
Alice:No,thank you.My mother has caught a bad cold.She has a high fever and coughs day and night.
 The doctor says my mother has to be in hospital for a few days.I would like to be with her.
Green : I understand.     53     ?
Alice:I hope to be back next Wednesday.
Green : That' s all right.     54     .
Alice : Thank you, Mr.Green.That' s very kind of you.I will write it immediately.
Green.     55     .
第51题答案是(　　)