下列烷烃的命名是否正确?若有错误加以改正,把正确的名称填在横线上:
(1)CH3—CH—CH2—CH3 2—乙基丁烷
CH2
CH3
(2)CH3—CH—CH—CH3 3,4—二甲基戊烷
CH3 CH2
CH3
CH3—CH2—CH2 CH2—CH3
(3)CH3—CH2—C—CH—CH—CH3 5—甲基—4,6三乙基庚烷
CH2 CH3
CH3