题目

You won't be able to make ________ of a word until you know all the _____ of it. A . use; uses B . usage; usages C . use; usages D . usage; uses 答案：C下列反应的离子方程式正确的是A. 铁与稀盐酸反应：2Fe＋6H＋=2Fe3＋＋3H2↑B. 氢氧化钠溶液与醋酸反应：OH－＋H＋=H2OC. 铜片插入硝酸银溶液中Cu+Ag+＝Cu2++AgD. 锌与硫酸铜溶液反应：Zn＋Cu2＋=Zn2＋＋Cu