Don't have your children ____ for hours doing their homework in ___ dark a roomA.sitting ,so B.sit

Don't have your children ____ for hours doing their homework in ___ dark a roomA.sitting ,so B.sit
Don't have your children ____ for hours doing their homework in ___ dark a roomA.sitting ,so B.sit ,such C.to be sitting ,so D.to sit ,such 为什莫 so such 怎样区别