C 分析:根據(jù)小數(shù)的乘法法則可知:0.8×0.8的積是兩位小數(shù),8×0.8的積是一位小數(shù),80×0.8的積是整數(shù),800×0.008的積是一位小數(shù),由此解答. 解答:0.8×0.8的積是兩位小數(shù),8×0.8的積是一位小數(shù),80×0.8的積是整數(shù),800×0.008的積是一位小數(shù),所以80×0.8的積最大; 故選:C. 點評:本題主要考查小數(shù)乘法中積的變化規(guī)律,注意積的小數(shù)位數(shù).