``` <form > <div class="form-group"> <select class="form-control"> <option value="武汉">武汉</option> <option value="长沙">长沙</option> <option value="贵阳">贵阳</option> </select> </div> </form> ``` ``` form div class="form-group" select class="form-control" ```  ``` <form action="" > <div class="form-group"> <select class="form-control" multiple> <option value="武汉">武汉</option> <option value="长沙">长沙</option> <option value="贵阳">贵阳</option> </select> </div> </form> ``` 显示如下