<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<html>
<body>
<div class="container">
<div class="row">
<div class="col-md-6">
<form class="form">
<div class="form-group">
<div class="input-group">
<span class="input-group-addon" id="month-addon">Month: </span>
<select name="control-month" class="form-control" aria-describedby="month-addon">
<option>January</option>
<option>February</option>
<option>March</option>
<option>April</option>
<option>May</option>
<option>June</option>
<option>July</option>
<option>August</option>
<option>September</option>
<option>Octomber</option>
<option>November</option>
<option>December</option>
</select>
<span class="input-group-addon" id="year-addon">Year: </span>
<select name="control-year" class="form-control" aria-describedby="year-addon">
<option selected="selected">2017</option>
<option>2016</option>
<option>2015</option>
</select>
</div>
</div>
</form>
