常用表面粗糙度的表示方法是在表面粗糙度的符号上加一数值，这个数值就是表面粗糙度参数轮廓平均偏差Pa，单位为μm。（）

A . A、去除材料 B . B、不去除材料 C . C、热轧 D . D、冷轧

A .https://assets.asklib.com/psource/2014112217522671914.png B .https://assets.asklib.com/psource/2014112217523215891.png C .https://assets.asklib.com/psource/201411221752408565.png D .https://assets.asklib.com/psource/2014112217524774230.png

A . 正确 B . 错误

A . 正确 B . 错误

A . ['['https://assets.asklib.com/psource/2014112217481916694.png B .https://assets.asklib.com/psource/2014112217482895704.png C .https://assets.asklib.com/psource/2014112217483675930.png

A .https://assets.asklib.com/psource/2014112217561949008.png B .https://assets.asklib.com/psource/2014112217562626602.png C .https://assets.asklib.com/psource/2014112217563615628.png D .https://assets.asklib.com/psource/2014112217564314782.png

A . 相同倍数 B . 小一号 C . 2倍 D . 1.4倍

A . 正确 B . 错误

A . 正确 B . 错误

A . 用 B . 随便 C . 不用 D . 必须

A .https://assets.asklib.com/images/image2/2017053111454386662.jpg B .https://assets.asklib.com/images/image2/2017053111454891369.jpg C .https://assets.asklib.com/images/image2/201705311145514520.jpg D . 其他

A . 任何加工 B . 去除材料 C . 不去除材料 D . 冲压变形

A .https://assets.asklib.com/images/image2/2017053111435179283.jpg B .https://assets.asklib.com/images/image2/2017053111435458737.jpg C .https://assets.asklib.com/images/image2/2017053111435742763.jpg D . 其他

A . 正确 B . 错误

A .https://assets.asklib.com/psource/2014112217540495612.png B .https://assets.asklib.com/psource/2014112217540495612.png C .https://assets.asklib.com/psource/2014112217540495612.png D .https://assets.asklib.com/psource/2014112217540495612.png

A . 正确 B . 错误

A .https://assets.asklib.com/images/image2/2017053111445041717.jpg B .https://assets.asklib.com/images/image2/2017053111445240290.jpg C .https://assets.asklib.com/images/image2/2017053111445567851.jpg D . 其他

符号<img src='https://img2.soutiyun.com/shangxueba/ask/18477001-18480000/18479807/2014122510403156820.png' />，表示用去除材料加工的方法得到的表面粗糙度Ra的上限值为（）。

A．{-*{1609298132173_2_1476716.png}*-} B．{-*{1609298132173_2_1476716.png}*-} C．{-*{1609298132173_2_1476716.png}*-} D．{-*{1609298132173_2_1476716.png}*-}