whAt DoEs thE pAssAgE mAinly DisCuss
A．whAt AstronomErs lEArnED From thE survEyor AnD Apollo spACE missions.
B．ChArACtEristiCs oF thE mAjor tErrAins oF thE moon
C．thE origin oF thE moon's CrAtErs.
D．tEChniquEs usED to CAtAloguE thE moon's lAnD Forms.