What is the cause of smoky exhaust?

Oil being burned in the combustion chamber otherwise oil leaking into the engine somewhere and is being burnt up through the combustion process and the smoke from the burnt oil comes out the exhaust

Some disadvantages to leasing a car is that you are counting on someone to give you money every week or month depending on what you decided and if they don't have all of it well what if you needed that money now you as well have to pay not in full. a disadvantages to purchasing a new vehicle is if it is used then not all the time will absolutely everything work. its almost like a trail and era. although if it is a new car they will try to though all these specials and deals at you in your lease and it can be very overwhelming if you are not use to it.