提示：Henry准备去上海开会，打电话到航空公司订票，工作人员Lillian接听了电话。（L＝Lillian; H＝Henry）
L: Hello! This is Air China. _____（51）?
H: Hello. I'd like to book a flight from Beijing to Shanghai.
L: Sure._____（52）?
H: This Saturday morning July 12.
L: OK. How many tickets?
H: _____（53）.
L: So, that's one ticket from Beijing to Shanghai.
H: _____（54）?
L: Well, that will be 1, 030 yuan.
H: OK.Can I book that now?
L: Certainly.
H: _____（55）.
L: You're welcome.
51._____?
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