古代的城墙是用石灰和泥土混合建造的。

Gǔdài de chéngqiáng shì yòng shíhuī hé nítǔ hùnhé jiànzào de.

Ancient city walls were built with a mixture of lime and earth.

工人们正在用石灰粉刷墙壁。

Gōngrénmen zhèngzài yòng shíhuī fěnshuā qiángbì.

The workers are whitewashing the walls with lime.

这座老房子的墙面还保留着当年的石灰涂层。

Zhè zuò lǎo fángzi de qiángmiàn hái bǎoliú zhe dāngnián de shíhuī túcéng.

The walls of this old house still retain the lime coating from back then.