题目

The situation in Haiti after the earthquake was all in a mess, ______ the increasing number of robbery cases. A. causing                             B. having caused          C. caused                    D. to cause 答案：A请用恰当的化学用语表示：（1）5个铜原子5Cu5Cu （2）4个氢离子4H+4H+（3）保持水的化学性质的最小粒子H2OH2O（4）碳酸钙中钙元素的化合价为+2价+2CaCO3+2CaCO3．