They are in the living room,on the sofa.中on the sofa 作什么成分?

They are in the living room,on the sofa.中on the sofa 作什么成分? Edward and Wendy are sitting on the sofa in the living room in the sofa 还是 on the sofa? in the sofa还是on the sofa They are on the sofa.是什么意思? they are on the sofa 对画线的部分提问(画线的是on the sofa) they sat on the sofa in the sitting room?改一般疑问句 on the sofa还是on sofa对? on the sofa还是on a sofa in the sofa 与on the sofa的区别 是sit in the sofa 还是sit on the sofa? 为什么是on the sofa,而不是in the sofa?