operating effectiveness operating efficiency operating efficiently operating element operating elements operating engineers operating entities operating entity operating environment operating environments operating equipment operating errors operating expenditure operating expenditures operating expense operating expenses operating experience operating facilities operating features operating field operating flights operating force operating framework operating frequencies operating frequency operating functions operating fund operating funding operating funds operating globally operating grant operating grants operating group operating guide operating guidelines operating handle operating head operating heavy machinery operating height operating hour operating hours operating illegally operating in operating in accordance operating in australia operating in china operating in iraq operating in mexico operating in parallel operating in russia operating in south operating in the area operating in the city operating in the field operating in the market operating in the united states operating income operating income and expenses operating independently operating information operating instruction operating instructions operating instructions can operating internationally operating it operating knob operating lamp operating language operating lease operating leases operating level operating lever operating leverage operating licence operating licences operating license operating licenses operating life operating light operating limits operating line operating lines operating location operating loss operating losses operating machine operating machinery operating machines operating manual operating margin operating margins operating mechanism operating mechanisms operating member operating method operating methods operating microscope operating mode operating mode switch