Bootstrap按钮问题:按钮杂乱，无法并排放置

<div class="btn-group" role="group" aria-label="Button group">
  <button type="button" class="btn btn-primary">按钮1</button>
  <button type="button" class="btn btn-primary">按钮2</button>
  <button type="button" class="btn btn-primary">按钮3</button>
</div>

<div class="btn-toolbar" role="toolbar" aria-label="Toolbar with button groups">
  <div class="btn-group mr-2" role="group" aria-label="First group">
    <button type="button" class="btn btn-primary">按钮1</button>
    <button type="button" class="btn btn-primary">按钮2</button>
    <button type="button" class="btn btn-primary">按钮3</button>
  </div>
  <div class="btn-group" role="group" aria-label="Second group">
    <button type="button" class="btn btn-primary">按钮4</button>
    <button type="button" class="btn btn-primary">按钮5</button>
  </div>
</div>