4. Number substituted cycloalkenes in the way that gives the carbon atoms of the double bond the 1-and 2 positions and that also gives the substituent groups the lower numbers at the first point of difference 1- Methylcyclopentane(1-甲基环戊烯)35 Dimethylcyclohexene(3,5二甲基环己烯) (not 2-methylcyclopentene) (not 4, 6-Dimethylcyclohexene)4. Number substituted cycloalkenes in the way that gives the carbon atoms of the double bond the 1- and 2- positions and that also gives the substituent groups the lower numbers at the first point of difference 1-Methylcyclopentene (1-甲 基 环 戊 烯 ） (not 2-methylcyclopentene) 1 2 3 3,5-Dimethylcyclohexene (3,5-二 甲 基 环 己 烯 ） (not 4,6-Dimethylcyclohexene) 1 2 3 4 5