before-after.html.erb

# before
     <%= form.fields_for :desc_translations do |trans_field| %>
      <div class="col-md-5">
        <%= trans_field.text_area :de, :value => form.object.desc_translations[:de], :class => 'form-control', :required => true %>
        <div class="help-block with-errors"></div>
      </div>
      <div class="col-md-5">
        <%= trans_field.text_area :'zh-CN', :value => form.object.desc_translations[:'zh-CN'], :class => 'form-control', :required => true %>
        <div class="help-block with-errors"></div>
      </div>
    <% end %>

# after
    <% translate form, :desc do %>
      <div class="col-md-5">
        <%= yield :class => 'form-control', :required => true %>
      </div>
    <% end %>