【单选题】There are following business statements for an information system:①A customer submit 0 or more orders;②An order can only be submitted by one customer. There are two classes in the system “Customer” an...
【简答题】S1:Do you have any rooms available?S2:There are two rooms free at the moment,but they are only available tonight.Q:Who is the second speaker most probably?A. An immigration officer B. A customs office...