题目

There is a great danger if the driver has been drinking alcohol or taking drugs, or _____ by speeding or breaking down traffic laws.    A. showing off       B. showing around  C. showing up       D. showing in 答案：A 解析: 略分子式为C4H8Cl2，结构中仅含一个 —CH3的同分异构体共有（不考虑立体异构）（     ）A．6种 B．5种 C．4种 D．3种