CH3−CO−CH3\mathrm{CH}_{3}-\mathrm{CO}-\mathrm{CH}_{3}CH3−CO−CH3
CH3CH2CHO\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHO}CH3CH2CHO
CH3CHO\mathrm{CH}_{3} \mathrm{CHO}CH3CHO
HCHO\mathrm{HCHO}HCHO