HO HoH CHOH C=O HoH丙醛糖CHoH丙酮糖 HO HOH HO Hoh HOH HOH CHOH HOH HOH HOH HOH HOH HOH CHOH CHOH CHOH 戊醛糖己已醛糖己已酮糖CHO CHOH CH2OH CH2OH C=O CH2OH CHO CHOH CHOH CHOH CH2OH CHO CHOH CHOH CHOH CHOH CH2OH CH2OH C=O CHOH CHOH CHOH CH2OH 丙醛糖 丙酮糖 戊醛糖 己醛糖 己酮糖