rpx相关问题

.pro_list{

flex-wrap: wrap;

height: 300rpx

}

.pro_item{

margin: 19rpx ;

text-align: center;

width:335rpx;

border: 1rpx solid #CCC;

height: 100rpx

}

<view class="pro_list">

    <view class="pro_item">

    </view>

    <view class="pro_item">

    </view>

    <view class="pro_item">

    </view>

</view>

为什么不是并排排列的求解答