7.在平面直角坐标系中,点A(-1,4)关于坐标原点O对称点A′的坐标是( )
| A. | (1,4) | B. | (-1,-4) | C. | (4,-1) | D. | (1,-4) |
6.
如图,一个螺母的实物图,它的俯视图应该是( )
0 293120 293128 293134 293138 293144 293146 293150 293156 293158 293164 293170 293174 293176 293180 293186 293188 293194 293198 293200 293204 293206 293210 293212 293214 293215 293216 293218 293219 293220 293222 293224 293228 293230 293234 293236 293240 293246 293248 293254 293258 293260 293264 293270 293276 293278 293284 293288 293290 293296 293300 293306 293314 366461
| A. | B. | C. | D. |