首先，我的目标是使两个输入字段内联，图片是附件：

Symfony允许我们通过对字段的form_widget使用attr和对form_label使用label_attr来设置表单字段的样式，但在这里我想对div应用一个样式，该div包含Symfony在分支中自动生成的label + input：

$builder
->add('language', ChoiceType::class, array(
    'choices'  => array(
        'FR' => 5,
        'EN' => 1,
     ),
    'label'      => ' ',
    'attr' => array('style' => 'float:left;width:40%'),
))
->add('level', ChoiceType::class, array(
    'choices'  => array(
        'Good' => 5,
        'Bad' => 1,
     ),
    'label'      => ' ',
    'attr' => array('style' => 'float:left;width:40%'),
));

result：样式已经应用到输入（在我们的例子中是select），div父项没有受到影响（保持空样式）：

<div id="homebundle_personnel_personnelLanguages_0">
   <div> <!-- the div that i want to apply a style -->
      <label for="homebundle_personnel_personnelLanguages_0_language" class="required"> </label>
      <select id="homebundle_personnel_personnelLanguages_0_language" name="homebundle_personnel[personnelLanguages][0][language]" style="float:left;width:40%">
         <option value="5">FR</option>
         <option value="1">EN</option>
      </select>
   </div>
   <div>
      <label for="homebundle_personnel_personnelLanguages_0_level" class="required"> </label>
      <select id="homebundle_personnel_personnelLanguages_0_level" name="homebundle_personnel[personnelLanguages][0][level]" style="float:left;width:40%">
         <option value="5">Good</option>
         <option value="1">Bad</option>
      </select>
   </div>
</div>