填空题
According to the schedule, the touring party will visit the Summer Palace and Tian’anmen Square today. You can leave your baggage in the Left Baggage Office and pick it up later this afternoon if it is too heavy to carry with you. The receipt of the baggage should be kept Carefully because you will need it. We will come to Summer Palace first and finish the tour at 2 p. m.. Then we are going to the destination of Tian’anmen Square without parking. So please don’t get off the sightseeing bus during the journey until the driver says that it is time for food and drinks and toilets. Please be on time!
Why should they keep the receipt carefully