题目内容：
阅读下列短文，回答题。 提示：Tom询问秘书Alice有无留言，秘书告诉他Mr．White希望将会面时间改在周五下午三点。不巧，Tom那时要去北京出差，但他周四下午有空。
( Tom = T ; Alice = A)
T: Good afternoon． Alice． 51 ?
A:Yes． Mr． White called and he wanted to change 52 ．
T:Oh? When does he plan to come then?
A: 53 ．
T: Well, I don' t think it' s a good time． I' 11 54 this Friday．
A:Shall I call him back and fix a time again?
T: Sure．
A:What time is good for you then?
T:Let me see． Thursday afternoon 55 ．
A : All right． I' 11 call him right away．
T：Thanks．
第51题 ________
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