书架上积了一层厚厚的灰尘，看来很久没人打扫了。

Shūjià shàng jī le yì céng hòuhòu de huīchén, kànlái hěn jiǔ méi rén dǎsǎo le.

A thick layer of dust has accumulated on the bookshelf; it seems no one has cleaned for a long time.

他用手指在桌面上划了一下，指尖全是灰尘。

Tā yòng shǒuzhǐ zài zhuōmiàn shàng huà le yíxià, zhǐjiān quán shì huīchén.

He drew a line on the tabletop with his finger, and his fingertip was covered in dust.

这间老房子到处都是灰尘，我们得好好收拾一下。

Zhè jiān lǎo fángzi dàochù dōu shì huīchén, wǒmen děi hǎohāo shōushi yíxià.

This old house is covered in dust everywhere; we need to clean it up properly.