Para.13 Computers turn on the lights,heating and essential household services before people arrive home from work. household:adj.used in homes or relating to homes or all the people in one family“家庭的，家 用的；全家人的” Computers turn on the lights, heating and essential household services before people arrive home from work. household: adj. used in homes or relating to homes or all the people in one family “家庭的，家 用的；全家人的” Para. 13