| A | B |
|---|
| Julius Caesar | greatest rulers in Rome |
| domesticated | trained to be useful to people |
| streetcars | cars that move on rails; trolleys |
| self-proppelled | moves by its own power |
| exhaust | fumes or gases released from an engine |
| smog | fog polluted with smoke |
| sensors | devices that respond to a signal |
| turbine | a machine that changes the motion of fluid into mechanical power |
| cadmium | a soft white metal used in some batteries |
| navigate | to steer |
| atmosphere | the air that surrounds the earth |
| prototype | first of its kind; a model |
| mass transit | public transportation |
| levitation | as if floating on air |
| automatic | moving or working by itself |
