单项选择题
A.(CH3)3C+B.CH3CH2+C.CH3+D.CH2=CHCH2+
A.CH2=CHCH3B.CH3CH=CHCH3C.CH3CH=C(CH3)2D.CH2=CH2
A.CH2=CHCH3B.CH3CH=CHCH3C.(CH3)2C=C(CH3)2D.CH2=CH2