使用 Flexbox 连续显示 4 个 div

我试图使用下面的 html 在一行中显示 4 个框。所以一排应该有 4 个盒子。我总共有 8 个盒子，有 2 行 4 列。

<div class="parent">
  <div class="child box1">A Child</div>
  <div class="child">
    <div class="box2">B Child 1</div>
    <div class="box3">B Child 2</div>
    <div class="box4">B Child 3</div>
    <div class="box5">B Child 4</div>
    <div class="box6">B Child 5</div>
    <div class="box7">B Child 6</div>
  </div>
  <div class="child box8">C Child</div>
</div>

它应该看起来像这样

A-Child   Child1   Child2    Child3
Child4    Child5   Child6    C-Child

我尝试过的CSS是

.parent {
  display: flex;
  flex-wrap: wrap;
}


.parent>.child {
  flex: 1 1 20%;
}

.box1, .box2, .box3, .box4, .box5, .box6, .box7, .box8 {
  height:100px;
  width:100px;
  border:10px solid red;
}

这是可能的display:contents but support因为目前的房产价值很差或有问题。

.parent {
  display: flex;
  flex-wrap: wrap;
}

.open {
  display: contents;
}

.box {
  height: 100px;
  width: 25%;
  border: 3px solid red;
  box-sizing: border-box;
}

<div class="parent">
  <div class="child box">A Child</div>
  <div class="child open">
    <div class="box">B Child 1</div>
    <div class="box">B Child 2</div>
    <div class="box">B Child 3</div>
    <div class="box">B Child 4</div>
    <div class="box">B Child 5</div>
    <div class="box">B Child 6</div>
  </div>
  <div class="child box">C Child</div>
</div>