______relatively costly, the engine is highly efficient and needs servicing infrequently.A

The device used to limit engine torque at various engine speeds is called a ________.

The engineers spent the whole night（work) ___________on the new device.

The difference between the cost and selling price is usually the__________．A.advantage###S

Engine coolant accumulating in the diesel engine lubricating oil can result from a _______

According to the passage, the principle of education should be______.A．the cost effectiven

Part of the cost of many articles is taken as tax by the government ________ the co