how sat drop down list in bootstrap 4 like a row and column
<div class="form-row">
<div class="form-group col-2">
</div>
<div class="form-group col-5">
</div>
<div class="form-group col-5">
</div>
</div>
<div clas="form-row">
<div class="form-group col-4">
</div>
<div class="form-group col-4">
</div>
<div class="form-group col-4">
</div>
</div>