如何不显示标签从密码字段在树枝

目前，我正在做我的论坛注册表…

当我在树枝视图中使用{{ form_widget(form.plainPassword }}时，我得到:

<div>
    <label for="fos_user_registration_form_plainPassword_first" class="required">First</label>
    <input id="fos_user_registration_form_plainPassword_first" name="fos_user_registration_form[plainPassword][first]" required="required" type="password">
</div>
<div>
    <label for="fos_user_registration_form_plainPassword_second" class="required">Second</label>
    <input id="fos_user_registration_form_plainPassword_second" name="fos_user_registration_form[plainPassword][second]" required="required" type="password">
</div>

RegistrationFormType.php

class RegistrationFormType extends AbstractType
{
    private $class;
    /**
     * @param string $class The User class name
     */
    public function __construct($class)
    {
        $this->class = $class;
    }
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('email', 'email', array('label' => 'form.email', 'translation_domain' => 'FOSUserBundle'))
            ->add('username', null, array('label' => 'form.username', 'translation_domain' => 'FOSUserBundle'))
            ->add('plainPassword', 'repeated', array(
                'type' => 'password',
                'options' => array('translation_domain' => 'FOSUserBundle'),
                //'first_options' => array('label' => 'form.password'),
                //'second_options' => array('label' => 'form.password_confirmation'),
                'invalid_message' => 'fos_user.password.mismatch',
            ))
        ;
    }
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => $this->class,
            'intention'  => 'registration',
        ));
    }
    // BC for SF < 2.7
    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $this->configureOptions($resolver);
    }
    public function getName()
    {
        return 'bissap_user_registration';
    }
}

通常，当我只使用form_widget时，标签不显示，但与此表单构建器配置标签仍然在表单中。