Прочитайте текст и заполните пропуски подходящими по смыслу словами.
The electrical system in a car can have either a positive or a negative 1_______. In both systems, the battery leads and terminals must be connected 2_______.
In a car with a positive earth, the positive terminal must be connected to the car body. The negative terminal must be connected to the electrical 3_______.
In a car with a negative earth, the positive terminal must be connected to the electrical system. The negative terminal must be connected to the 4_______ body.
earth
correctly
system
car