For example, a flashlight contains a circuit whenever it's turned on--the current flows from the battery's positive terminal, through the switch (which is on), through the filament of the light bulb (which glows), and back to the battery's negative terminal.
(a flashlight; contains; a circuit whenever it's turned on--the current flows from the battery's positive terminal, through the switch (which is on), through the filament of the light bulb (which glows), and back to the battery's negative terminal) (it; 's turned on back; ) (the switch; is; ) (the filament of the light bulb; glows; )
a flashlight it the switch the filament of the light bulb
contains 's turned on back is glows
a circuit whenever it's turned on--the current flows from the battery's positive terminal, through the switch (which is on), through the filament of the light bulb (which glows), and back to the battery's negative terminal