___ the fuel oil has to be preheated.

The selection of an oil depends _____ on the operating conditions, the design of the engine and the type of fuel to be burned.

Fuel oil is thought to be one of the main factors _____ the operation and maintenance of a

According to the conversation, the use of fossil fuels ______.A．should be banned in order

When centrifuging heavy fuel oil, an important factor to consider is the _____（1) flow rat

Fuel has to be injected into the engine at a high pressure so that it _____ correctly.A.is

We seem to be light on fuel. The underlined part means______.A．be easy to getB．have small