题目

The parents rushed to the school, only ______ that their son had left without a word.        A. to tell B. to be told   C. being told           D. having told 答案：B 解析: 略 下列各组物质表示同一物质的是 [　　] A．氢氧化钠　生石灰 B．氢氧化钠　熟石灰 C．碳酸钠　　纯碱 D．二氧化碳　水