     
     override func viewDidLoad() {
         super.viewDidLoad()
-        
         configUI()
     }
     

        if backgroundScrollView.contentOffset.y < 0 {
            backgroundScrollView.setContentOffset(CGPoint.init(x: 0, y: SCREEN_HEIGHT), animated: false)
        }
        
    }
    
    //MARK: - 下落敌机

            else if enemyAp.isMember(of: EnemyAirplanBig.self) {
                afterHitDo(enemyAp, 500)
            }
        }
        //清除敌机炮弹
        for enemyShell in enemyShellsArray{
            removeEnemyShell(enemyShell)
        }
        ///清除炮弹
        for shells in shellsArray{
