<!DOCTYPE html>
<style>
  table {
    table-layout: fixed;
    width: 100%;
    border-collapse: collapse;
  }
</style>
<table>
  <tbody>
    <tr>
      <td colspan="4">Spanning.</td>
    </tr>
  </tbody>
  <tbody>
    <tr><td>1</td><td>2</td><td>3</td><td>4</td></tr>
  </tbody>
</table>