问如何正确对齐bootstrap窗体按钮？

EN

<div role="form">
    <div class="form-group">
        <label>Username</label>
        <input type="text" class="form-control"/>
    </div>

    <div class="form-group">
        <label>Password</label>
        <input type="password" class="form-control"/>
    </div>

    <div class="checkbox">
        <label>
            <input type="checkbox"> Remember Me
        </label>
    </div>

    <button class="btn-info btn">Log in</button>                            
</div>