H OH HO、 H-C-OH H-C-OH H-C-OH HO-C-H HO-C-H HO-C-H or H-C-OH H-C-OH H-C-OH H-C-OH H-C H-C- CH2OH CH2OH CH2OH D葡萄糖的环形和异头结构D-葡萄糖的环形和异头结构 C O CH2OH H C OH HO H C H OH OH H C HO H C OH OH H C H C OH C H H HO H C CH2OH O C C O CH2OH H C HO H C H H C OH H C OH or