5.下列命题正确的是( )
| A. | 若m>n,则mc>nc | B. | 若m>n,则mc2>nc2 | ||
| C. | 若m>b,b<c,则m>c | D. | 若m+c2>n+c2,则m>n |
17.下列几何体中,主视图相同的是( )

0 283048 283056 283062 283066 283072 283074 283078 283084 283086 283092 283098 283102 283104 283108 283114 283116 283122 283126 283128 283132 283134 283138 283140 283142 283143 283144 283146 283147 283148 283150 283152 283156 283158 283162 283164 283168 283174 283176 283182 283186 283188 283192 283198 283204 283206 283212 283216 283218 283224 283228 283234 283242 366461
| A. | ①② | B. | ①④ | C. | ①③ | D. | ②④ |