6．听下面一段材料，回答第15至第17题． 15．Wnere does the conversation probably take place？ A．At a Lost and Found Office． B．In a supermarket． C．In a bookshop． 16．What was the man doing at about 8：00this morning？ A．Buying books B．Take a taxi． C．Looking for his bag 17．What do we know about the man's bag？ A．It's expensive． B．It's large． C．It's black．
