石膏

Second, because gypsum is so soft (it has a hardness of 2 on the Mohs' scale), it can be easily scratched and damaged by tools, boots—even a fingernail.

第二是石膏太柔软以致它很容易被工具、靴子甚至是指甲划伤或损坏。

The reasons of iron ions content overproof in grade Ⅱ desalting water system,such as variation water quality,contamination of regenerant , operation adjustment of pretreatment system and switching operation of bed were discussed.

对二级脱盐水系统中铁离子含量超标的原因，如来水水质发生波动、再生剂受到污染、预处理系统操作调整、床体运行切换等进行了论述。

You were hired to drum up new business, so go and do it.

公司雇你招徕新业务，你就做你的事好了。