这个句子怎么变被动语态?

题目

这个句子怎么变被动语态?
Did they hear us sing songs in the next room?
____________________________in the next room?
初二被动语态里的(百思英语),还有Were the songs we sang heard by them in the next room?里面的 that 可以去掉吗?

答案

Did they hear us sing songs in the next room? ____________________________in the next room?应该改为：Were the songs that we sang heard by them in the next room?颇有难度的英语题呢...我只能说:"的确是好...