A:to get; to get
B:to getting; to getting
C:to getting; to get
D:to get; to getting
先秦
秦汉
魏晋南北朝
隋唐五代
宋辽金
元明
清
北方
87%
76%
61%
68%
50%
29%
26%
南方
13%
24%
39%
32%
71%
74%
地壳中含量最多的金属元素是()