题目

The doctor came up and asked me ______the day before.   A.what had I eaten               B.what I have eaten   C.what have I eaten              D.what I had eaten 答案：D用铂电极电解AgNO3饱和溶液（溶质的质量分数为17 %）,当银完全析出时，阳极上放出5．6 L气体（标准状况），此时溶液密度为1．04 g·cm-3。求：（1）阴极上析出银的质量；（2）电解前AgNO3溶液的质量；（3）电解后溶液的物质的量浓度。