There is a comfortable chair to sit on .为什么加on 而有的句子不加介词,像用take part而不用take part in最好举几个例子,

dalian is a place where you can fain natural scenes of mild climate 翻译A Chief Introduction of daliandalian is a place where you can fain natural scenes of mild climate 翻译谢谢!还有下面的话，和上面的标题别忘翻译！..comfortab Is there a window? There is a middle there is a cat there is a problem Is there a school Is there a house___? There is a Is there a. there is a There is a kitshen. There is a pair over is village a there there (.) There is a long r______ there. There( )(be)a football match,is there. there is a baby horse over there. there ,a there,is ,phone如何排列? where there is a life,there is a hope.