他们受雇于工厂，厂房及类似机构的维修部门，也可受雇于水暖承包商，或者他们可能是自营企业。
They are employed in maintenance departments of factories, plants and similar establishments, by plumbing contractors, or they may be self-employed.
他们受雇于电业承办商，维修部门的大型机构，例如医院或工厂，或者也可以自谋职业。
They are employed by electrical contractors, maintenance departments of large institutions, such as hospitals or industrial plants, or they may be self-employed.
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