Yii中的redirect跳转

1.   Yii::app()->user->returnUrl = Yii::app()->getBaseUrl()."/step/show/id/1";
     $this->redirect(Yii::app()->user->returnUrl);
2.   $this->redirect(array('step/show','id'=>1));
3.   $this->render('index',array('post'=>$questions));
4.   $this->renderPartial('field_show',array('field'=>$field,'key'=>++$key,));