[解析]
M:Hi,Lucy!
W:Oh,hi,Jim!Where are you going?
M:I'm going to the post office.I want to send a letter to my sister.
W:By the way,what are you going to do this weekend?
M:Nothing much.
W:A picnic?
M:Sounds great!I think it will be very interesting.When shall we start and where shall we meet?
W:How about eight o'clock tomorrow morning outside the school gate?
M:I want to spend more time in the forest.Shall we make it a little earlier?
W:Well,what about half past seven?
M:All right,half past seven.I'll be there on time.
W:And we need to take some food and drink with us.What about going shopping together this afternoon?
M:Sure.I will call you then.
W:OK.See you later.