16.下列图形中是正方体的展开图的是( )

| A. | ①②③ | B. | ②③④ | C. | ①③④ | D. | ①②④ |
12.下列图形中,是正方形的展开图的是( )
| A. | B. | C. | D. |
10.把(x-y)看成一个整体,则化简(x-y)2-3(x-y)-4(x-y)2+5(x-y)的结果是( )
0 283090 283098 283104 283108 283114 283116 283120 283126 283128 283134 283140 283144 283146 283150 283156 283158 283164 283168 283170 283174 283176 283180 283182 283184 283185 283186 283188 283189 283190 283192 283194 283198 283200 283204 283206 283210 283216 283218 283224 283228 283230 283234 283240 283246 283248 283254 283258 283260 283266 283270 283276 283284 366461
| A. | 2(x-y)-3(x-y)2 | B. | 2(x-y)2-3(x-y) | C. | (x-y)-3(x-y)2 | D. | 2(x-y)2-(x-y) |