如何在Twitter Bootstrap 3中居按钮？ - How to center buttons in Twitter Bootstrap 3?

问题：

I am building a form in Twitter Bootstrap but I'm having issues with centering the button below the input in the form. 我正在Twitter Bootstrap中构建一个表单，但是我遇到了将表单中输入下方的按钮居中的问题。 I have already tried applying the center-block class to the button but that didn't work. 我已经尝试将center-block类应用于按钮，但这不起作用。 How should I fix this? 我该怎么解决这个问题？

Here is my code. 这是我的代码。

<!-- Button -->
<div class="form-group">
    <label class="col-md-4 control-label" for="singlebutton"></label>
    <div class="col-md-4">
        <button id="singlebutton" name="singlebutton" class="btn btn-primary center-block">
            Next Step!
        </button>
    </div>
</div>

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解决方案：

参考一： https://stackoom.com/question/1Wjn3
参考二： How to center buttons in Twitter Bootstrap 3?