agricultural mechanics repair agricultural machinery similar to a motor machanic
car mechanic motor mechanic vehicle mechanic
an auto mechanic
A mechanic, or motor mechanic, or car mechanic.
The mechanic did my car's engine for free.
Maybe a truck mechanic, or an airplane mechanic.
Mechanic
There is no mechanic. Sorry.
agricultural
Bill Mechanic's birth name is William M. Mechanic.
The passive equivalent is "The car will be repaired by the mechanic."
You need a repair licence to open a repair shop. You don't need a licence to be a mechanic but, it would be to your benefit to be a certified mechanic.
"An auto mechanic" is correct, and "a auto mechanic" is not. "Auto" begins with a vowel - typically, these will be preceded by "an" rather than "a".