what are three main things that operating system handles

what are three main things that operating system handles What are the three main concerns for business today regarding computer ethics What are the three types of business organizations?Please list the main features for each type.请用英语回答, what are the big three? what is the three main effect of management on organization what are the main elements of humanism? What are the main functions of Parliament? What are a main function of computer? What are three kinds of culture? What are three big industries in Ontario? covering three main stages What are the main features of religion in the UK? what are the main differences between是什么意思?急用 what are the main orgins of english words? what are the main consequences of the Norman Conquest? what are the main characteristics of polymeric materials?Material physics I'm sorry three.和What are you sorry for? what class are you in?（用class three回答）