CHO CHO CHO H--COH H-COH HOC-H HOC-H HOC-H HOC-H H-COH H--cOH HOC-H H一cOH H-COH H-COH CH2OH CH,OH D-glucose D-galactose D-mannose D一葡萄糖D一芈乳糖D-甘露糖醛 糖