<img src、"http://hebei.ouchn.cn/pluginfile.php/61593/question/answer/585347/4/246728/3-04-A%E3%80%81B.png" alt="" width="32" height="27"><em> </em>，上侧受拉
<img src、"http://hebei.ouchn.cn/pluginfile.php/61593/question/answer/585347/4/246729/3-04-A%E3%80%81B.png" alt="" width="32" height="27">，下侧受拉
<img src、"http://hebei.ouchn.cn/pluginfile.php/61593/question/answer/585347/4/246730/3-04-C%E3%80%81D.png" alt="" width="43" height="27">，上侧受拉
<img src、"http://hebei.ouchn.cn/pluginfile.php/61593/question/answer/585347/4/246731/3-04-C%E3%80%81D.png" alt="" width="43" height="27">，下侧受拉