xu：hi,Professor Xiao
xiao：hello, xu rui,i am glad to see you ,where are you going ?
xu：i want to go to the library.oh sorry ,i am late,the library wii be closed.i must go !
xiao：ok，see you.
xu:thanyou ,byebye!
xu：hi,Professor Xiao
xiao：hello, xu rui,i am glad to see you ,where are you going ?
xu：i want to go to the library.oh sorry ,i am late,the library wii be closed.i must go !
xiao：ok，see you.
xu:thanyou ,byebye!