A:H2C=CH﹣CH=CH2 1,3﹣二丁烯
B: :间二甲苯
C: 2,6﹣二甲基﹣5﹣乙基庚烷
D: 2﹣乙基﹣1﹣丁烯
19100 ____ 291000 ____ 7910000 ____
选择最佳应答语( )
— I'll buy _________ of them, so I can give one to my friend, Helen.