长时间无人打扫，房间的地板变得满是灰尘。

The floor in the room became much ___dustier after being left uncleaned for so long.

这幅画的颜色更灰暗，给人一种怀旧的感觉。

The ___dustier colors in this painting create a nostalgic mood.

会议结束后，话题变得越来越枯燥无趣。

After the meeting, the topics became ___dustier and less engaging.