假设你是王力，国庆节期间你准备和家人去上海看世博。你想了解有关订票方面的具体情况，例如：可否在网上订票？团体购票是否可以打折？可否因故取消订票？你在互联网上查到了一份门票价格表（见下表），但还有些具体信息不明确。请给相关人员发一封信，询问有关情况。

Ticket Prices

	Regular	Peak	Special
Adults	￥ 300	￥ 350	￥ 350
Children（aged 5 to 11）	￥ 200	￥ 230	￥ 230
Seniors（65 or over ）	￥ 100	￥ 150	￥ 150

Children under 5?
参考词汇：取消cancel  折扣 discount  要求：词数120左右；可根据内容要点适当增加细节，以使行文连贯。注意：信的开头与结尾已给出。
Dear Sir / Madam,                                                                  
        My family and I are planning a visit to Shanghai World Expo in the coming vacation．                                                                         
                                                                                   
                                                                                
                                                                                       
                                                                                 
                                                                     Yours                                                                                            
                                                                     Wang Li