Six carbons =0 H H H H 0 H H- OH HO-C-H H-C-OH HO-C-H H-C-OH HO-C-H H-C -OH HO-C-H H-C-OH H-C-OH HO- -C-H HO-C-H H-C-OH H-C-OH HO- C-H HO-C-H H-C-OH H-C-OH H-C-OH H-C-OH HO-C-H HO-C-H HO-C-H HO-C-H H-C-OH H-C-OH H-C-OH H-C-OH H-C一OH H-C-OH H-C -OH H-C一OH CH2OH CH2OH CH2OH CH2OH CH2OH CH2OH CHOH CH2OH D-Allose D-Altrose D-Glucose D-Mannose D-Gulose D-Idose D-Galactose D-Talose D-Aldoses (a)