盲巷是指长度超过（）m的不通风巷道。
A.5
B.6
C.8
参考答案：B
已知分子式为C10H14的烃，其一溴代物的同分异构体有四种，则该烃的结构简式可能是 （ ）
You __________ tell anyone about this - it's a secret.[ ]
A. needn't
B. mustn't
C. couldn't
D. wouldn't
