题目

 Since Margot found it difficult to settle in a new place, she felt ______ that the family had to move.       A. upset                      B. crazy               C. happy                     D. easy 答案：A下列变化过程中，化学键没有被破坏的是 [     ]A.HCl溶于水 B.干冰升华C. 固体NaCl熔融 D.煤矿中瓦斯（主要成分CH4）遇火爆炸