   neutral   What can I do for you?     neutral   Would you recommend some materials on the World War Two?  
    neutral   Have you found a particular item from the card catalogue?     neutral   Yes, but I don't think they are enough for me.  
    neutral   Oh, maybe you can find something from the New York Times, or the Washington Post during that period.     happiness   
 That is an good idea. Thanks so much! 
 That seems very reasonable. Thanks a lot!  
   sadness   Sorry to trouble