Many football fans attached great importance to the two matches, because China needed to beat Iran to ensure ________ for the Asian Cup semi-finals.

A．outcome

B．conservation

C．qualification

D．occupation

文献记载“钢铁是杂炼生（生铁）鍒（熟铁）为刀镰者。”此文献提到的金属冶炼技术发明于 [ ]

A．春秋战国时期

B．两汉时期

C．魏晋南北朝时期

D．隋唐时期