JSFiddle - React, Tailwind, and code Playground

HTML

<div class="but1">
  <b style="">bla bla1 + start</b>
</div>
<div class="but2">
  <b style="">bla bla2</b>
</div>
<div class="but3">
  <b style="">bla bla3</b>
</div>
<div class="block_work">
</div>

JavaScript

setInterval(function() {
  var rere = [];
  rere[0] = $(".but1").clone(); start();
  rere[1] = $(".but2").clone();
  rere[2] = $(".but3").clone();


  var i = Math.floor(Math.random() * rere.length);
  var result5 = rere[i];
  $('.block_work').html(result5);

}, 2000);

function start() {
  // нужный код
}