37 general building construction services; general civil engineering, namely, basic construction services; bricklaying, tile laying, and block laying services; installation, repair and maintenance of machinery, namely, pumps, freezers/freezing equipment, turbines, boilers, burners, fans, heaters, air-conditioning apparatus, metalworking machines and machine tools, chemical-mechanical polishing machines used in the manufacture of semiconductors; electrical contracting; electrical work, namely, installation and repair of electric appliances, installation and repair of electric distributing wires; telecommunication work, namely, construction, installation, maintenance and repair of telecommunication equipment and systems; repair and maintenance of burners, boilers, pumps, freezers, freezing equipment, computers and computer peripherals, central processing units, programmed data carrying electronic circuits or magnetic disks; maintenance, inspection and management, namely, planning, designing, operating, and repair of boilers; repair and maintenance of plants, namely, machines and apparatus for treating water, sewage water, industrial water, industrial waste water, night soil, refuse, industrial waste, industrial waste gases and heat; installation, repair and maintenance of equipment for supplying water to or draining water from buildings; installation, replacement and cleaning water receptacles or water tanks in elevated positions; repair and maintenance of pumps and fans; installation and cleaning of pumps, boilers, electric power plants, petro-refining plants and petro-chemistry plants and other plants, namely, machines and apparatus for treating water, sewage water, industrial water, industrial waste water, night soil, refuse, industrial waste, industrial waste gases and heat