使用bootstrap，您可以很容易地用row&；col类元素，如下所示:

    <div class="row">
        <div class="col-6 offset-3">
            <!-- Your carousel code here -->
        </div>
    </div>

这将使你的旋转木马50%的宽度的页面。

请试试这个，

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<!-- CSS only -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css" integrity="sha384-JcKb8q3iqJ61gNV9KGb8thSsNjpSL0n8PARn9HuZOnIxN0hoP+VmmDGMN5t9UJ0Z" crossorigin="anonymous">

<!-- JS, Popper.js, and jQuery -->
<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.1/dist/umd/popper.min.js" integrity="sha384-9/reFTGAW83EW2RDu2S0VKaIzap3H66lZH81PoYlFhbGU+6BZp6G7niu735Sk7lN" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js" integrity="sha384-B4gt1jrGC7Jh4AgTPSdUtOBvfO8shuf57BaghqFfPlYxofvL8/KUEfYiJOMMV+rV" crossorigin="anonymous"></script>

<div class="container">
  <div class="row">
    <div class="col-md-6 h-auto">
      <div id="carouselExampleControls" class="carousel slide w-100 h-100 mx-auto text-center" data-ride="carousel">
        <div class="carousel-inner bg-dark">
          <div class="carousel-item active">
            <img src="https://i.stack.imgur.com/txnXq.png" class="img-fluid w-50" alt="...">
          </div>
          <div class="carousel-item">
            <img src="https://i.stack.imgur.com/dyPJ0.png" class="img-fluid w-50" alt="...">
          </div>
          <div class="carousel-item">
            <img src="https://i.stack.imgur.com/4bBjx.png" class="img-fluid w-50" alt="...">
          </div>
        </div>
        <a class="carousel-control-prev" href="#carouselExampleControls" role="button" data-slide="prev">
          <span class="carousel-control-prev-icon" aria-hidden="true"></span>
          <span class="sr-only">Previous</span>
        </a>
        <a class="carousel-control-next" href="#carouselExampleControls" role="button" data-slide="next">
          <span class="carousel-control-next-icon" aria-hidden="true"></span>
          <span class="sr-only">Next</span>
        </a>
      </div>
    </div>
    <div class="col-md-6 mt-lg-0 mt-3 h-auto mx-auto text-center">
      <h4 class="h-100 bg-success d-flex align-items-center justify-content-center">Carousel side content here</h4>
    </div>
  </div>
</div>