Impurities in the fuel oil will affect the operation of the engine， which has （） the use of separator and some other devices.

这个效应主要是由于在该物质中存在杂质。This effect is caused by __________ there are impurities in the material.?

中国大学MOOC: 这个效应主要是由于在该物质中存在杂质。This effect is caused by __________ there are impurities in the material.（使用同位语从句）

What is the main factor causing Rayleigh scattering? A: Defects equivalent to the wavelength scale of the fiber B: Defects equivalent to the geometric size of the fiber C: Defects equivalent to the length of the fiber D: Impurities

In the process described by the woman, why is the coal burned A: To produce a gas containing carbon and hydrogen. B: To remove impurities from methanol. C: To heat the reactors. D: To prevent dangerous gases from formin

Why S-glass is stronger than E-glass? A: The formula is different between S-glass and E-glass. B: S-glass has less impurities than E-glass. C: The diameter of S-glass is smaller than that of E-glass. D: S-glass is processed at higher temperature.

According to the passage, how did Bessemer method make the mass production of steel possible A: It directed air at melted iron in a furnace, removing all impurities. B: It slowly heated iron ore then stirred it and heated it again. C: It changed iron ore into iron which was a substitute for steel. D: It could quickly find deposits of iron ore under the ground.

In<br/>the acid-base titration of aspirin, neutral ethanol is required to be<br/>used as the solvent. What is the meaning of calling "neutral"?() A: neutral<br/>to the indicator used B: pH=7 C: ethanol<br/>to remove acidic impurities D: It<br/>is neutral to methyl orange E: relative<br/>to the tested substance