nCH3CH=CHCH3+nCH2=CHCH=CH2----->-[-CH(CH3)CH(CH3)-CH2CH=CHCH2]n-你就说分开写呀：nCH3CH=CHCH3----->-[-CH(CH3)CH(CH3)-]n- nCH2=CHCH=CH2----->-[-CH2CH=CHCH2-]n-