JSFiddle - React, Tailwind, and code Playground

HTML

<div>over the <span>Triangle, a few months later</span>, another plane disappeared. A ship named the Sandra.</div>

CSS

div {
    font-size: 15px;
    width: 50%;
    line-height: 30px;
}
span {
    position: relative;
    height: 15px;
    white-space: pre;
}
span:after {
    position: absolute;
    content:'2';
    width: 100%;
    height: 100%;
    top: 100%;
    left: 0;
    border-top: 1px solid black;
    text-align: center;
    font-size: 9px;
    line-height: 15px;
}