Twitter bootstrap 如何水平对齐选择框

如何将以下选择框彼此垂直对齐

到期日：月：年

//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css

到期日

尝试将标签类更改为复选框内联

    <div class="form-group">
            <label class="checkbox inline" for="expirymonth" class="col-sm-2 control-label">Expiry Date </label>
                <div class="col-sm-10">
                <select id="expmonth" ng-model="expirymonth" ng-change="setcardmonth(expirymonth)" ng-options="e.month for e in cardmonth"/>
                    <select style="margin-left: 200px" ng-model="expiryyear" id="expyear" ng-change="setcardyear(expiryyear)" ng-options="y.year for y in cardyear"/>
                    </div>


        </div>