answer: #Person1# suggests that #Person2# take a sweater and a raincoat to Shanghai.
documents: #Person1#: You're going to Shanghai tomorrow, are you ? 
  #Person2#: That's right . Do you think it'll be cold? 
  #Person1#: It might be. You'd better take a heavy sweater with you. The nights are usually quite cold at this time of year. 
  #Person2#: Do you think I'll need a cotton coat? 
  #Person1#: Not for now, I think , But I believe there'll be rain, so take your raincoat with you.