Annual utilization hours will not be less than 6500 hours in the first year after half a year of starting up and commissioning. Later on annual mean operationhours is 7900 hours.
锅炉投产调试运行半年后的第一年，年利用小时不低于6500小时，以后年平均运行小时7900小时。
2
The delicate surgical operation took five hours.
这精细的外科手术花了五个小时。
《牛津词典》
3
An automobile service station manager draws up guidelines for gas stations and automotive repair shops and decides on hours of operation, assigns job duties and sets prices for services and products.