<div class="dropdown">
  <button type="button" class="btn btn-primary dropdown-toggle" data-toggle="dropdown">
  پیشفرض
  </button>
  <div class="dropdown-menu">
    <a class="dropdown-item" href="#">فعالیت</a>
    <a class="dropdown-item" href="#">فعالیت دیگر</a>
    <a class="dropdown-item" href="#">یک فعالیت دیگر</a>
  </div>
</div>

<div class="btn-group">
  <button type="button" class="btn btn-primary">پیشفرض</button>
  <button type="button" class="btn btn-primary dropdown-toggle dropdown-toggle-split" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    <span class="sr-only">باز کردن دراپ‌دوان</span>
  </button>
  <div class="dropdown-menu">
    <a class="dropdown-item" href="#">فعالیت</a>
    <a class="dropdown-item" href="#">فعالیت دیگر</a>
    <a class="dropdown-item" href="#">یک فعالیت دیگر<</a>
    <div class="dropdown-divider"></div>
    <a class="dropdown-item" href="#">لینک مجزا</a>
  </div>
</div>

<!-- Large button groups (default and split) -->
<div class="btn-group">
  <button class="btn btn-secondary btn-lg dropdown-toggle" type="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    دکمه بزرگ
  </button>
  <div class="dropdown-menu">
    ...
  </div>
</div>
<div class="btn-group">
  <button class="btn btn-secondary btn-lg" type="button">
    دکمه بزرگ مجزا
  </button>
  <button type="button" class="btn btn-lg btn-secondary dropdown-toggle dropdown-toggle-split" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    <span class="sr-only">باز کردن دراپ‌دوان</span>
  </button>
  <div class="dropdown-menu">
    ...
  </div>
</div>

<!-- Small button groups (default and split) -->
<div class="btn-group">
  <button class="btn btn-secondary btn-sm dropdown-toggle" type="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    دکمه کوچک
  </button>
  <div class="dropdown-menu">
    ...
  </div>
</div>
<div class="btn-group">
  <button class="btn btn-secondary btn-sm" type="button">
  دکمه کوچک مجزا
  </button>
  <button type="button" class="btn btn-sm btn-secondary dropdown-toggle dropdown-toggle-split" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    <span class="sr-only">باز کردن دراپ‌دوان</span>
  </button>
  <div class="dropdown-menu">
    ...
  </div>
</div>

<!-- Default dropup button -->
<div class="btn-group dropup">
  <button type="button" class="btn btn-secondary dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
  دراپ‌آپ
  </button>
  <div class="dropdown-menu">
    <!-- Dropdown menu links -->
  </div>
</div>

<!-- Split dropup button -->
<div class="btn-group dropup">
  <button type="button" class="btn btn-secondary">
  دراپ‌آپ مجزا
  </button>
  <button type="button" class="btn btn-secondary dropdown-toggle dropdown-toggle-split" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    <span class="sr-only">باز کردن دراپ‌دوان</span>
  </button>
  <div class="dropdown-menu">
    <!-- Dropdown menu links -->
  </div>
</div>