In a sim environment, there are 3 modes:
Build Mode Live Mode Buy Mode
Live mode is the only mode in which Sims can be controlled, and it is the only mode where time can pass. The user has control over the time in most circumstances and can adjust the speed at which time passes. Live mode is the only mode where improvements to a lot cannot be made.
Buy mode allows players to purchase items from an object catalog and place them on the current lot, sell objects that are on the current lot, and arrange objects on the current lot.
Build mode is used mainly for architectural and construction work.