不能将第二个div浮动到第一个div的右侧？

My code is very basic

我的代码非常基础

HTML:

<div class="blog cf">
    <div class="left_article_content">
        <img width="100" height="100" src="https://placehold.it/100x100" alt="test">
    </div>
    <div class="right_article_content">
        <h1>Test Header</h1>
        <p>
            This is a test This is a test This is a test This is a test This is a test This is a test This is a test 
        </p>
    </div>
</div>
<div