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CDL Practice Test
General Knowledge
Air Brakes
Combination Vehicles
Doubles and Triples
Tanker Vehicles
Hazardous Materials
Transporting Passengers
CDL Combination Vehicles Practice Test
Question 1 of 3
Before backing under a trailer that you've just hooked to your tractor you should:
A
Ground the trailer
B
Make sure the fifth wheel has been removed
C
Hook up the service and emergency lines
D
Hook up the electrical lines
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