题目

下列离子反应方程式中，属于水解反应的是 A．CN－＋H2OHCN＋OH－             B．NH3·H2ONH＋OH－ C．HCO＋H2OH3O＋＋CO           D．H2CO3HCO＋H＋ 答案：AI was doing my homework last night ________ I heard a cry ________ help．A.then; ofB.while; inC.at the same time; toD.when; for