residual|residuals

该理论留下了一些残余问题没有解决。

The theory leaves behind certain ___residual problems unsolved.

过滤后，杯底留下了一些残留物。

After filtering, there were some ___residuals left at the bottom of the cup.

音乐家们每年都会收到歌曲播放的剩余版税。

Musicians receive annual ___residual royalties for their song plays.