image.png
<form role="form">
<input type="text"><span class="help-inline">行内解释文本</span>
<input type="text"><span class="help-block">行外解释文本</span>
</form>
<form role="form">
<input type="text"><span class="help-inline">行内解释文本</span>
<input type="text"><span class="help-block">行外解释文本</span>
</form>