我正在使用getbootstrap.com的引導程序。我想在SAVE和CLEAR按鈕之間留出空間。我也希望他們能夠將中心對齊到文本框上。我怎樣才能做到這一點?如何在兩個按鈕之間留出空間?以及如何將它們對齊到中心
<div class="form-group">
<label for="trucktype" class="col-sm-2">Truck Type</label>
<div class="col-sm-4">
<select id="trucktype" name="trucktype" class="form-control" tabindex="2">
<option value="volvo">Service Wheels</option>
<option value="saab">Boom Truck</option>
<option value="mercedes">Crane Truck</option>
<option value="audi">Pole Trailer Truck</option>
</select>
</div>
</div>
<div class="form-group">
<label for="truckloadcapacity" class="col-sm-2">Truck load capacity</label>
<div class="col-sm-4"><input type="text" name="truckloadcapacity" id="truckloadcapacity" class="form-control" tabindex="3"></div>
</div>
<div class="form-group">
<label for="truckdesc" class="col-sm-2">Truck Description:</label>
<div class="col-sm-4"><textarea class="form-control" rows="3" id="truckdesc" tabindex="4"></textarea></div>
</div>
<div class="form-group">
<label for="truckphoto" class="col-sm-2">Truck Photo</label>
<div class="col-sm-4"><input type="file" name="file" id="truckphoto" class="form-control" tabindex="5"></div>
</div>
<!-- BUTTONS start -->
<div class="row">
<div class="col-sm-4">
<div class="form-group">
<input class="btn-primary btn-lg col-sm-4" type="submit" value="Save">
<input type="reset" class="btn-default btn-lg col-sm-4" name="clear" value="Clear">
</div>
</div>
</div>
<!-- BUTTONS end -->
</form>