sit ()the back row用in还是on为什么

sit ()the back row用in还是on为什么 是sit on the chair还是sit in the chair 是sit in the sofa 还是sit on the sofa? Sit on the grass.还是 Sit in the grass? 是sit in the armchair还是sit on the armchair? 英语太烂求帮忙The ueher seated us in the back row为什么saet要用被动 坐在椅子上用sit on the chair 还是sit in the chair "坐在第.排"是否这样说：sit in the ...row.例如：sit in the third row,sit i 三·改错题we sit on the front row.she sits in front of the classr The man _____ in the back row is our headmaster.为什么 我坐在沙发上是 I sit in the sofa.还是 I sit on the sofa. the chair is very comfortable to sit in 这个地方为什么要用in而不用on