rEsEArCh into thE mAtEriAl CulturE oF A nAtion is oF grEAt importAnCE BECAusE ______.
A．it hElps proDuCE nEw CulturAl tools AnD tEChnol0g~,
B．it CAn rEFlECt' thE DEvElopmEnt oF thE nAtion
C．it hElps unDErstAnD thE nAtion's pAst AnD prEsEnt
D．it CAn DEmonstrAtE thE nAtion's CivilizAtion