题目

下列化学用语表示不正确的是 A. 氢离子结构示意图：  B. 中子数为20 的Ar原子：Ar C. 二氧化硅的结构式：O=Si=O    D. 乙烯的结构简式：CH2=CH2 答案：C—I must be leaving now. It'll be three hours' drive to get there. —________ [　　] A．Good-bye.B．Take care. C．Take it easy.D．What can I do for you?