xy手动添加图例不成功求指点

ymz

xx = (/1860,1890/)
yy = (/9.7,9.7/)
dum1 = gsn_add_polyline(wks,plot,xx,yy,reslines)
dum2=gsn_add_text(wks,plot,"RCP4.5",1900,9.7,restext)
; gsn_polyline(wks,plot,xx,yy,reslines)
; gsn_text(wks,plot,"RCP4.5",1900,9.7,restext)

yy = (/9.69,9.69/)
reslines@gsLineColor       = "blue"   ; line color
reslines@gsLineDashPattern = 1   ; dash pattern
dum3= gsn_add_polyline(wks,plot,xx,yy,reslines)
dum4=gsn_add_text(wks,plot,"RCP8.5",1900,9.69,restext)
; gsn_polyline(wks,plot,xx,yy,reslines)
; gsn_text(wks,plot,"RCP8.5",1900,9.69,restext)
添加不成功
请大神指点迷津