有些工作者服务于设备如电暖气和空调的制造商。他们还要出差到安装了系统的地方，为他们更新或改进已安装的系统。
Some work for equipment manufacturers, such as the makers of heating and air conditioning systems, and they travel to installation sites to upgrade or modify those systems.
近几年来，花岗石已广泛用于外墙饰面，但还存在不少问题， 如采用旧的安装工艺导致变色；
During recent years, granite has been widely adopted for external wall' s facing blocks and decoratives.
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