css float left合理布局换行不一切正常难题的处理

<div class="block">
        <div></div>
    </div>
    <div class="block">
        <div></div>
    </div>
    <div class="block">
        <div></div>
    </div>
    <div class="block" >
        <div id="special"></div>
    </div>
    <div class="block">
        <div></div>
    </div>
    <div class="block">
        <div></div>
    </div>

.block {

            width: 25%;
            padding: 10px;
            float: left;
            box-sizing: border-box;

        }
        .block div {
            background-color: pink;
            width: 100%;
            height: 280px;
        }
        #special {
            height: 280px;
            background-color: green;
        }