As soon As pErson gEts "thrEsholD pAins", hE shoulD______.
A．tElEphonE thE DoCtor immEDiAtEly
B．First rEliEvE thE strEss AnD tEnsion whiCh CAusE thE pAins
C．wAit to lEt thE pAins rEACh A CErtAin point
D．tAkE pAin-killEr