单项选择题
A.①②③④ B.⑤⑥⑦⑧ C.①②⑦⑧ D.③④⑤⑥
A.3种 B.4种 C.5种 D.6种
A.(CH3)2CHCH2CH2CH3 B.(CH3CH2)2CHCH3 C.(CH3)2CHCH(CH3)2 D.(CH3)3CCH2CH3